Practically speaking, & thinking as a woodworker i agree.
A wood frame is never going to be perfect over time, but it has some excellent perhaps overlooked benefits in the modern era, including decent stability with changing humidity within typical values in a human living space; and excellent thermal stability across the same.
Slate is quite stable, although it needs support and shimming in the thickness typically used for pool tables. Accepting those 2 materials, there does not seem to be much in terms of "adjuster" systems that would excel shims and levels for leveling.
Plus there are what, a billion legacy tables out there? Playing fine?
Thinking technically, though, Rasson is probably the way things will trend in the future. Commodity level tables with ease of set up, steel tube frames, built in leveling systems at similar cost to Diamond. It is even easy these days to start to imagine an automatic leveling system. Perhaps for only a few $K upcharge.
Slate is probably still the cheapest bed material. Especially as 3 pc slate sets.
OTOH, glass is more or less easy to make flat, weighs less than 2/3 wt of slate, and is somewhat stiffer & stronger (many x stronger for tempered) than most slate. Not thinking of "designer" tables which already include some. Thinking of using materials to build a commodity table, even "barboxes" the way Diamonds are now.
We are probably at a cusp where the old materials vs new are just about a toss up cost wise, but it could flip quickly. Wood sure has gotten expensive lately. And scarcer.
One issue with steel or alloy tube frame is that it is not thermally stable. That may or may not be a factor for tables, in "typical" living spaces.
My sense is that slate is more thermally stable than glass (can't find data" but at those levels probably irrelevent. Rail systems based on extrusions could be engineered with elastomers & wood to play as well as anything, and the esthetics easily tailored as well.
I have always wondered why everything holding the slate up was not made of steel. Undoubtedly its stronger than wood (at least the common available wood) It seems like it would be easier to design and build a simple leveling system for. Although steel is not thermally stable I think it is more stable than wood at normal temps and is not affected by moisture.