Why no cheap synthetic replicas of old shields etc?

For example, one company has "training" swords made of some type of synthetic material, they are cheap af, and built like tanks. Why don't they do this for shields and stuff? It doesn't have to be thick, and it doesn't have to be as effective as it was in real life, but something for the budget crowd. I wanted to buy a Greek aspis shield but I'll probably have to settle for making my own out of a 3 foot diameter round pine table top. I'd even settle for a riot shield shaped to look like the real ones.

Is it expensive to make stuff like that or what, is that why nobody does it?
Would kick em in the nuts