BBB "not in this century"
I don't know about that. This century is just starting out.
Thing is, the synthesiser (my original example not just from my most recent post, but also my first post in this thread) is designed to replace real existing instruments. Not just improve them.
Do synths manage this even today? Nope, there are still full blown orchastras and there are even some artists that DO hire string and horn sections to play on their albums.
I don't believe in absolutes. Harpsichords make it into studios, folks still use acoustic guitars and others will opt for analogue over digital. Hell, I still think that beta beat the pants off of VHS, but that's another rant.
My point is that synthesisers are used more often than real instruments because they do sound very good and to most untrained ears perfect.
I think that the thing that strikes me in this conversation isn't weather or not PODs sound better or do a better or even equal job to close mic'd amps.
I think what I'm reacting to is the "It'll never become an accepted substitute" argument.
That's not a very open minded attitude.

Amplifiers are designed to fulfill a purpose. Propellers are designed to fulfill a purpose too. Jet engines fulfill the purpose a bit better. Maybe that's a bad example because the point in your post is that some things
replace for the sake of improvement while others seek to
mimick something out of existance. But can you say with certainty that amplifiers are the best of all possible worlds? There can never be a technology to surpass them?
I resubmit the propeller/jet analogy.
Now, proplellers, Model T's, Horse drawn wagons and wooden clubs for boppin' folks with are all still being used today in the 21'st century, but most are entering the realm of novilty over nessessity. It happens to everything sooner or later.