Yes, definitely I'd buy 21mm track and points. The sales opportunity lies in the new modellers joining. One economical approach might be to create the sleepers for RTR track using 3-D printing, to allow an adjustable print-to-order. The track could be sold as simple kits -- sleepers in strips with rails to be inserted.
Meanwhile, I bought Irish broad gauge sleepers from the ScaleFour Society and bullhead rail in code 75. (Thanks, Jeremy Suter, for the help.) Just need uninterrupted free time. Working towards a combined MGWR Sligo line with Collooney Jct. to Dromod and the Cavan & Leitrim from Dromod to TBD.
A now-often-cited article about "the Long Tail" of a niche market might help explain how to think about models of Irish broad gauge (and Irish 3-foot RTR on 12 mm track). You create the niche, in part, that people haven't articulated in masses -- you don't respond to an existing mass market. The idea is used for a lot of niche-market sectors, such as a rare books library or historical museum that specializes in certain research subjects. https://www.wired.com/2004/10/tail/