Not everyone is able bodied and has nice showers at work to change in.
As for showering, I think that will probably start to matter less as time goes on. In the last few years, in the Pacific NW, I've noticed it's become somewhat acceptable to show up to meetings a bit sweaty, if you've just gotten off your bike. At least, among the business meetings I attend, of course.
It's an honest question, really, I don't know! (though I know what I'd prefer!) What do you think?
Denholm Reynholm in the stress episode of The IT Crowd may have been hilarious in London, but he wasn't too far off the mark in Portland.
He wasn't too far off the mark for Reading (boring town west of London, where it's set). That was entirely the point of that episode.
(While a long-term trend away from sterile-squeaky-clean might be useful, I still have a strong emotional aversion to "sweaty at console": I'm not comfortable that way if it's me, plus everyone starts smelling when sweaty. At one job, I even washed up quickly using the hand sink, just to avoid this)