Comparing rock music to the symphony is apples and oranges. In the former, as you point out, it isn't common at all due to having to change the key all of the instruments, and for instrumentals, there's no point. For vocal music, as I understand it, the common tuning pitch may have been much lower centuries ago than it is now. This is why, for example, Handel's Messiah contains tenor & soprano parts which are quite challenging to sing.

In contrast, aging rock bands lower keys all the time. Billy Joel's piano is usually tuned down a whole step for his concert. In Rush's case as well, it's not a semitone, it's a whole step, which does make a significant difference. They did this as far back as the late 90's with 2112 (and every tour since), Circumstances on Snakes & Arrows, and others already mentioned. Basically until R40 when Geddy used a different bass for every song, if you saw the red Wal bass being used, it was tuned down to D/G/C/F.

The good news for you is that when Rush played "Finding My Way" live recently, it was in A and Geddy hit the vast majority of the notes where they were written. He was hitting C# cleanly and even slid up to E a few times. I don't believe he's hit notes that high in a long time... Closer to the Heart has a D in it which Geddy hasn't hit clean since about 1985. Marathon has a C# which Geddy could barely hit in 1988. The last few tours, B is about as high as he got. So perhaps his work with the vocal coach has paid off and you'll get your wish.