I’m guessing you’ve never owned an AI with the quick lock barrel? It’s easy as can be and dead nuts repeatable. I could afford any rifle I want or any combination of rifles, but I wouldn’t trade my PSR for any of them.
OP isn't going to buy an AI, so it is what all us poors have to do with a budget action. You don't need an AI for a quick change barrel, flats on the barrel and an action wrench are as easy as it gets.
Also, changing bolt face AND a barrel is tiring when you are at the range trying to shoot. But, we are talking about a PRS/hunting/ELR rifle. Every time you switch, yeah zero will be really close, but if it is off .1 you have to shoot a group to verify and change if necessary. You might have to slip turrets or deal with offsets in your ballistic software.
Also, I like to shoot my rifles. If my barrel gets hot on my hunting rifle, I want to shoot my PRS rifle while I wait. I can't go changing hot barrels on and off, that is stupid. I wouldn't do that with an AI if I had it and I could snap my fingers and barrels would change. I would still have to verify dope so I know if the miss was me or my zero.
Now, for some people who maybe swap a barrel for training and shoot a whole day with it and swap back the match barrel and zero, it works. But, the case for the switch barrel is MUCH MUCH narrower in practical terms than one would think. If you have specific "seasons" and set your rifle up by season, like hunting season, ELR season, and PRS season, then that might make more sense changing it three times a year. But, don't fool yourself into thinking the switch barrel rifle means you will be shooting different cartridges every time you go out. I did switch my match gun to a hunting barrel and left it for a couple months, but I didn't have matches and once I got my hunting rifle zeroed up, I stopped messing with it till the hunt. That was a specific hunt that called for a shorter barrel inside a blind.
In the end, if you want multiple calibers, start with something like Savage actions and prefit barrels and shoot the dang thing. It is 90% of a custom, IMO. Then, when you can afford it buy a Bighorn and screw the prefit onto that and keep plugging away. You can buy used and sell used. It is what I have done.
My Proof prefit was just as accurate on my Savage as it was on my Nucleus action. The Savage action was not as sweet as my Nucleus under time in PRS, but truthfully, my skills had far more to do with my score than the Savage action. I love my Nucleus, and sold all my other rifles to consolidate to customs. But, if I had to start over again, I wouldn't change a thing. Savage rifles aren't awesome, but they were good to me.