Good is the enemy of best.....
And best (price) is the enemy of high quality.
Lots of good, valid points have been raised already, lets add just a few more...
One is the general, overall consumer market. Firearms are a consumer product, but they are not a product like most others. Making and selling guns is not the same as making and selling bricks. Times change, tastes change, manufacturing methods change, laws change, all of these, and more, have an effect on the market.
Using an inflation calculator is an interesting comparison, but it is not entirely a valid reference, because the cost of items has not been a linear change. Some things cost more than they used to, even adjusting for inflation. Changes in supply, demand, and taxes have an effect that is not figured into the calculations for "buying power" then and now, because it is specific to the item(s) being discussed. And, it is also relative to the individual's finances who are buying those products. Also, the calculator provided (thanks for the link, btw) "only" goes back to 1913!
We, as Americans of the last 50 years have gone through a tremendous change in what we buy, and the way we buy things. The cash price of many, many items is of smaller concern than it used to be, due to credit cards and financing. 50+ years ago, the only things that got financing were major purchase items, like houses, cars, and major appliances. Stores often did "lay away" for other items, which seems to have mostly gone away today (other than at some gun shops), which allowed you to buy goods over time, and you didn't get the goods until they were paid for.
Today, buy it on plastic, and take it home, paying for it over time (with interest) is the common method. So, lots of things can get sold, even though the buyers might not have the cash on hand to pay for them, at the time. That is one change that didn't exist in the past. In the "old days", you didn't get your gun until you had completely paid for it.
The firearms market used to be a larger segment of the economy than it is today. We had a larger rural population, with both a need and a desire for firearms than we do today. Even the urban population contained a higher percentage of hunters and sportsmen than it does today. So, the (sporting) market has shrunk. A partial balance is the increase in the personal defense market, but I don't think it evenly balances out.
More modern designs, particularly in handguns, focuses more on function and less on fit and finish than they used to. This is something that began during WWII, and the basic idea has carried on. Look at the guns made before WWII. All of them, including the military ones were made using traditional gun making methods, milled steel, assembled by skilled/semi skilled craftsmen, and intended to give a lifetime of good service. This also has an effect on today's market, as many of those guns are still in use today.
WWII saw the beginning of the "make it cheap, make it fast, make it work well enough to do the job, and don't worry about how long it lasts" philosophy on a large scale. Planned obsolescence has become a way of life in manufacturering in recent decades (more so than ever in the past), however, that doesn't work well in the firearms industry. Everything can be worn out, and guns are no exception, but traditionally, guns don't wear out from normal use, during an everage user's lifetime. Part of that is the way guns were (and are) built, but a lot of it comes from the fact that the ordinary gun owner rarely, if ever, used their guns enough to actually wear them out.
So, it is ingrained in our psyche that "good guns don't wear out (or have problems), and if they do, they weren't good guns". Or something close to that. The information age (Internet) also has an effect. Today, when somebody has a problem with a gun, they post it, and the whole world knows about it, instantly. This makes it seem like there are more problems than there used to be, because we are hearing about them, constantly. In the good old days, the only time you heard about guns with problems was when you talked to people who had had them. And those rare occassions when magazines actually gave unfavorable reports.
Labor costs have been mentioned, and that's another truism. Skilled labor costs more in the USA than in other nations today, because of who, and what we are. Take a look at a typical pocket pistol made in Germany between the wars. Fine fit and finish. Many I have seen even have the insides polished, and not just those areas necessary! Labor costs were much lower than today, so they could take the time to finish products to a high level of quality. We did the same thing. Guns were a product of pride, as well as marketability.
Guns got sold by their reputation, not just their performance. Making and selling a high grade product was part of ensuring continued sales. You don't see that much today.
Brand loyalty is still pretty strong in the firearms market, but not like it was. And its almost non-existant in the rest of the consumer market. There its the bottom line, cost. As long as the product is good enough to work, long enough to satisfy the consumer, that is what gets built, and sold.
I think perhaps the best way to explain some of it is that a century ago, gun companies were in the business of making guns to make a profit, while today, they seem to be in business to make a profit, by making guns.
We have created this situation, in guns, and other products, by our insistance on low cost goods, and acceptance of lesser quality (or the perception of lesser quality) as long as the price is good.
Playing with the inflation calculator was entertaining, and using my (perhaps fallible) memory I found a few instances where a straight calculation does not equate to market costs today. Here are a few examples,
a can of soda, $.25 in 1976 calculates to $.96 today. In my area, they sell for less than that (but not a lot). A gallon of premium gasoline $0.60 in 1976, calculates to $2.31 today. I would be very happy to only pay $2.31 a gallon today! A ruger Super Blackhawk .44 Mag had msrp of $135 in 1974. The calculator says that today that is $599.16. MSRP on Ruger's website $670! A Marlin .444 was msrp at $145 in 1974. Calculator says $643.54. One is on a website right now for $498.
So, we pay both more, and less for our guns today, than we used to.
With all the "advances" in manufacturing (CinC machining, etc.) it seems that guns cost both more, and less than they did even a few decades ago. It is very ...model specific.
As to the customer service, I can't say much, directly. I have had very, very few instances of using any gun company's customer service. Ruger did me fine, the one time (about 20 years ago) that I did have a problem. Today? All I know about it is what I read on the Internet!