Almost all artists today are, like these cave-dwellers of yore, getting neither big bucks nor tenure for what they do. You argued that that was a good reason to suspect that these Venus figurines were essentially porn; it seems to me that that logic would dictate that the same reasoning would be applicable to most art today.
There IS plenty of erotic art today – both for private reasons (the artists like making it) and because they get commissions for it. I know artists that have done both.