Mikrotik said that fast path is a feature of Linux kernel. Why can’t it be implement on x86 ? I known there is no HWNAT in Tilera chipset but It indeed have fast path. So the reason is they can’t or just they don’t want to?
For many reasons I suspect.
There are too many variations on x86 platforms.
It is easier to support platforms that Mikrotik have developed end-to-end, and they also know how they will perform under various loads.