"It's a huge waste of computer resources if you occasionally, I dunno, clothe your figures."

But how many actually clothe them?

I might be wrong but I honeslty think only a small percentage of the figures out there get fully clothed. There's a lot of clothed figures in the galleries here, but likely a million more times unclothed figures doing the rounds on the net.  One other thing to consider is that clothing your figure doesn't always negate the need to worry about UV seams, where the head map meets the body map being a good example of this.

So, even clothed, splitting what is supposed to be a continuous surface into a multiple surface, can still be a problem for the end user even when clothed.  I remember years ago, I did render where the figure was actually clothed (yes, I actually did one with clothes :-P), but I had to give her a neck band just to hide the stupid seam between the head and body maps.  I didn't want her to have a neck band, but the top she had on was close to being a V-top so it was either that, a scarf, or have her look like she'd done a head swap :-D