Okay, you're technically correct. How about this then? The SI of stone is 7 by the way.
If you think this will collapse, please tell me which block, specifically, won't work.
To be clear, I'm not saying you can build a stilt base with granite, since you can already do that. But I am saying you can build even bigger, heavier, less supported stilt bases than you already could. It's not necessarily a deal breaker, but it's something to consider, especially since zombies will
not bang on the support right now, and we don't know what the solution to stilt bases will be or what assumptions the design may be predicated on to work.