And there is a ton of money shoveled to projects like this - I've worked on a few over the years. The Advanced Research Projects Agency (ARPA) has probably funded 10's of billion$ on seemingly stupid ideas. Some of them (like the internet) actually have been demonstrably useful. Many of them may appear to be more Darwin Award category but I'd rather the money was spent there than on weaponry.
This particular experiment seems a bit grade-school level but I'm thinking that all the major powers have already looked at the physics of hardening. Probably back to those days when all we had were earthenware berms.