Actually, even the scientists working on Excalibur said that current materials science and engineering wasn’t up to the task and wouldn’t be for a couple decades. It wasn’t that the idea didn’t work but that the then-current tech wouldn’t let it work efficiently enough to make it a production weapon.
It’d be like trying to make an iPhone equivalent with 1950’s era vacuum tube technology. It can be done, but it’s going to be the size of a house and have a battery life measured in minutes plus you can forget about tucking it into your pocked.