At that price, the titan is (duh, like all of them are/were) most likely aimed at developers to have a card that is perhaps representative of more mid-high end RTX3xxx series performance for next year.
i.e., the developer can develop and run the new game on his titan and by the time the software is released that performance will be upper-mid-range in say 2020.
Well. Game developers, and those using the cards to actually make money with. Or gamers with way too much disposable income (of which there are a few).
As above, i very much suspect that RTX is going to be one of those things that WILL take off, but its going to be on the newer 7nm cards before its “worth it”.
Right now developers are dabbling with it in inconsequential ways because the hardware support isn’t out, and the hardware that IS out for them to experiment with on the consumer side still isn’t fast enough to do anything significant with.
i.e., RTX isn’t a “bust” per se. But it’s way early days yet.