Yes, I'm aware that a good quality instrument is likely to stay in tune longer than a cheapo one. But they still need tuning from time to time, during a long set. It depends how you play it though.

Tuning on stage is a necessary evil, IMO. I've seen artists who don't bother to retune during their act, maybe because they don't want to waste time, with the result that they play out of tune, which offends my ears. I'd rather they spent a short time retuning than listen to a cacophony (accent on 'short'!)