Comment by bjw4

PPPoE is still very common in the UK, even over fibre. I think it’s something to do with allowing multiple providers on the same infra.

The encapsulation requires a lot of CPU power, and on non specialised x86 hardware you end up needing a highly clocked CPU to get gigabit speeds.

OpenWRT is Linux based so has a multithreaded implementation.

My Flint 2 router has some sort of hardware acceleration so hammering a gigabit line shows <1% CPU, leaving lots of overhead for things like Docker.