these folks are doing their best to combine and extrapolate mathematical principles to extremes (an approach which, nota bene, did prove spectacularly successful in explaining huge parts of the universe earlier on) but the results of this exercise has been exceedingly poor for almost half a century now.

at some point we must give up or admit that the nature of the game has changed. In a sense even the tiniest piece of experimental evidence that probes (or at least remotely reflects) the actual inner workings of "quantum" spacetime would be worth more than this enormous cumulative effort to infer what is happening on the basis of abstract symmetries and what not.