While that's true, I'm not sure it's because of something inherent in IPsec vs WireGuard. It's more likely due to the fact that hardware accelerators have been designed to offload encryption routines that IPsec uses.
One wonders what WG perf would look like if it could leverage the same hardware offload.
Exactly this. I would love to see a commercial product with a hardware implementation for WireGuard, but it does not yet exist. IPsec, however, is well supported.