For just about every action both old and new, I agree. The costs and hassles do add up quickly especially is all you want is a hunting rifle. If building a target rifle or for some particular non factory set up, maybe.
Now, I am a constant tinkerer and change cals and rifles all the time. That has gotten expensive in both money and time. My solution - the Savage/Stevens actions.
Being modular, just about anything can be changed easily and cheaply. I can go from standard to magnum bolt face, from feeding skinny cases to fat cases with little problem with feeding. All in a few minutes and simple hand tools. So I now have the perfect platform. All I need is more barrels and accessories.
Is it worth it for one permanent swap, of course not, but for the constant experimenter, ideal.
Jerry