Wasted effort reinventing things and rediscovering their limits and failure modes is a major downside of the ageism that is rampant in the industry. There is nobody around to say “actually this has been tried three times by three previous generations of devs and this is what they learned.”

Another one: WASM is a good VM spec and the VM implementations are good, but the ecosystem with its DSLs and component model is getting an over engineered complexity smell. Remind anyone of… say… J2EE? Good VM, good foundation, massive excess complexity higher up the stack.