This reply touches on what I think may, or hopefully eventually will, happen. It needs to just become a permanent acceptable go to thematic option, instead of a genre that comes back, and subsequently goes away. Like when a martial arts movie comes out we don't think "shaw bros kung fu flicks are back"... they are just always with us forevermore.
I also think the myriad of new westerns, many direct to streaming and not on the OP's list, are really poorly done, which doesn't help boost the supply and demand. I also fully admit this perception could be my bias to Spaghetti Western though, as the contemporary westerns I see are so flooded with perfectly laundered wardrobe from westernemporium.com, shiny wear free chrome blank-firing weapons from maxarmory.com along with their poorly executed cgi muzzle flashes set against the same fakey-looking relatively clean old west rent-a-town movie set - that I just become more and more disenchanted... and bitter.
Maybe niche... or "cult" is the answer - and man I have always felt Spaghettis are an untapped peg for that pigeon hole. if only more filmmakers knew about/embraced them for what they really are. I mean if an exec/distributor never heard of a Spaghetti Western and someone had just wrapped one up, a good one that wears its homages on its sleeve, they could easily pitch it as a Psychedelic Mad Max Samurai film set in an anachronistic southwest. How could that not sell!