I myself still play both DCSS and DF in ASCII mode, but it seem reasonable to presume that the reason that old hands like us are fine with the ASCII look is because everyone who wasn't fine with it has self-selected themselves out of the sample. If their goal with the DF Steam release is to bring in new players (and compete with the likes of e.g. Rimworld, whose players are accustomed to graphics), then I see this as a sound decision.
(And of course, seconded that DF's nonsensical command UI is going to continue to stymie their efforts here.)