For me, it's exciting to see a new owner of an XZ, Gmarcus, posting and being enthused about the bass.
New ownership really died down after Gibson closed MusicYo and sales of new XZs ended. Apparently, Spirit XZs don't change hands very often, at least judging from eBay and Talkbass and other online sales/trade venues.
Although Gibson's dealer network is still selling XT's, it doesn't appear that many of those are moving these days. I would say most brick-and-mortar stores do not stock XTs. What few are sold new nowadays are probably selling from online retailers. I don't expect that Gibson will keep the XTs in production too much longer.
Headless basses, particularly the "stick" style ones, are always going to be a bit of a trendy or faddy thing. Not everyone wants that look. There are definite advantages to the Steinberger designs, and the only way to discover them is to own a Spirit, Synapse, NS Design, or any others of the family.