OK, so back in the 1960s when the Python was brand new, there were no S&Ws that could compete with it.
Depends on how you define "compete".
S&W didn't have anything to compete with it. Nothing. S&W had the N frame Registered Magnums, but those were not a regular production item, plus they were heavier than most people liked.
The Registered Magnum ended production during WWII. S&W didn't restart production of N frame .357s until 1950, and then the gun was called the .357 Magnum, and was a regular production item.
Between 1955 and 1957, Colt introduced the Python, and S&W introduced the model 19, changed the name of the .357 to the Model 27 when they went to their number system in 1957 and also introduced a lower price N frame .357 designated Model 28 Highway Patrolman.
And they had the K frame Combat Masterpiece (similar to the later models 19 and 66 like you have), which was really too light for the 357 Magnum, had a light barrel, and had an annoying habit of the frame or forcing cone cracking when fed a steady diet of 357s.
The S&W Combat Masterpiece is a .38 Special. The model 19 was called the "Combat Magnum". And. as to the frame being "too light" I'd say that's a judgement call, considering that the model 19 served, and came to dominate the police revolver market for over a decade without any significant reports of frames or forcing cones cracking, and shooting the available .357 Magnum ammo while they did it.
Take a look at the ammo of the day. .357 Magnum was only loaded with 158gr bullets until the 1970s. The issue of forcing cones cracking didn't happen for almost 15years of service use, it didn't show up until the factories began loading the 125gr bullet, and police depts changed their policies so that practice was no longer done with .38s but with the new 125gr duty load.
The combination of a new, hot load (that didn't exist when the gun was designed) and constant use of that load exposed a weakness in the Model 19 and 66 barrel profile in the forcing cone area, one that was only found due to the hot 125gr loading and never showed up in over a decade+ of shooting the 158gr loading.
This problem did not happen with the Python, nor did it happen with other S&W .357s, the 27 and 28.
A friend of mine, a S&W gunsmith, would often tell me how he could tune a S&W 19 to be "as good as" an out-of-the-box Python, but by then you had to put as much money into a S&W you might as well just buy the Colt.
This makes me curious when your friend told you this, and what he charged for the work. My guess would be that if he charged so much that "you might as well buy the Python" means he charged a lot.
In 1974 the model 19 cost $150, the Python $215. The model 27 cost $175 and the model 28 cost $135. By 1978 the model 19 was up to $180, while the Python cost a whopping $350!!
You could, almost literally, buy 2 (two) model 19s for the cost of a single Python.
S&W switching to frame mounted firing pins didn't happen until the 90s, whether it was to reduce hammer weight (why??) or to better suited to the MIM hammer, I have no idea.
But in the mid 1980s, S&W introduced the L frame. As soon as I saw it I understood what had happened. S&W introduced a 357 size frame with a heavy underlug match barrel and target trigger/hammer. THey basically built a Python on a S&W frame. At that point, I knew the Python was dead, there was nothing to set it apart from a Smith.
S&W built a gun with a ribbed barrel and a full underlug that resembled the Python on the outside. The rest of the gun was quite different. And there was still something that set the Python apart from the L frame S&W, Pythons COST MORE.
Also, interestingly enough, those S&W L frames weighed exactly the same as the N frame guns that "were heavier than most people liked".
The fact that Colt lasted as long as it did in the LE revolver market from the 60s on was more a matter of brand loyalty than anything else. Large metro depts that bought guns in the hundreds often kept buying Colts, because, well. they're
Colts, and a product of known historical quality.
But the rest of the LE community, particularly smaller depts where officers and deputies bought their guns themselves, almost no one bought Colts, they simply cost too much.
Even when the depts covered the cost, or issued a voucher, many chose the lower cost of the S&W (and later, Ruger) over the high price of the Colt line.
When its a choice of buy a Colt,. or buy a S&W and a holster and a gunbelt and maybe some other stuff for the same amount of money, well, history shows what most people chose, and S&W was the clear winner.