They did for a very long time, but digital is catching up fast-especially with the current trend of silent stages. Metallica and Def Leppard use Axe-FX IIIs for their live shows, Mark Knopfler used Kemper. There are plenty more, but those were the "big names" that popped into my head. Lots of younger bands are running Helixes, as is Richie Castellano of Blue Oyster Cult. Digital is out there if you take the time to look for it, probably just as much as tube amps are if you take the time to look for them.