There's something unnatural about putting electronic components inside of musical instruments. Steel-string guitar is such a new type of instrument, it's not used in classical music. If every guitarist tried to use your approach, there would be no Champs available. Even 5 watts is louder than I like however, when at home. And when playing with drums, a Champ isn't loud enough, unless mic'd.
Many guitarists have a tube amp and effects unit.
And they would buy an isolation cabinet if they knew about them. And I've taken the idea to its logical conclusion by defining an entire standalone unit including final power amp and monitor cabinet. I dislike the complexity of this system, but it could be manufactured as a compact and inexpensive system. Such a system has several powerful and valuable capabilities unlike any guitar processing approach we've seen. This system deserves to exist, despite its complexity.