Revolvers can handle loads and cartridges that semi's cannot,
Sorry to disagree, but I don't see this as being true. There is nothing you can shoot out of a revolver (and I'm talking about fixed ammunition, not cap & ball) that cannot be fired out of a semi auto design.
Now, if you are going to talk about specific guns, then there is some truth to that statement, but as a general and absolute statement, it's simply false.
IF you adjust the history of chemistry, so that "modern" smokeless powder was developed at the same time as self contained cartridges, THEN, you have a viable possibility of developing the semi auto at the same time as cartridge revolvers.
Black powder simply does not have the right pressure curve to operate the normal designs of semi auto actions. AND, blackpowder gets the guns very HOT, in a very small number of shots. More so, than smokeless.
You might be able to make a functional semi auto shooting black powder using the long recoil action system. Might be manageable in a rifle, and I think would be in a crew served weapon, if the design also made allowances for the fouling and for cooling. I don't see a practical way to do that in a handgun.
Also, consider this, how long it took the world's militaries to switch from the revolver to the semi auto pistol. And how much longer it took police agencies. Despite the fact that there were 'reliable" semi autos for many, many years, revolvers held sway for a long time, and not simply because they were traditional.