It's not an 'electric vs. acoustic' thing. It's a 'which key' question. If anything, it's easier for Jon to hide his terrible voice in a wall of noise that comes from full band performances.

If we're solely using Jon's voice as a measuring stick, he should not only stop playing 'original versions' of all of their songs (even half step down).

Realistically, it would make sense for him to 'pull a Coverdale' and start playing most of their catalogue even lower than half-step down. I actually expected him to do that in 2015, but he didn't, so he probably is not going to do it now either. He thinks that all of his audience are idiots that can't hear how bad he sounds. Sadly, in many cases, he's almost correct.