That reminds me of the when the openWRT and other open source guys were complaining that the home gateways of the time did not have a big enough CPU to max out the uplink (10-100mbps at the time), and instead built in hardware accelerators. What they did not know was that the hw accelerator was merely an even smaller CPU running a proprietary network stack.
That doesn't sound quite right to me. The worst CPU bottlenecks I recall for consumer routers running OpenWRT were mostly when doing traffic shaping (to compensate for bufferbloat in ISP equipment), not a complete inability to forward traffic fast enough. And when line speed really wasn't achievable with software routing, the hardware deficiency that mattered most was probably memory bandwidth rather than CPU core performance.
The kind of offload most prevalent on consumer routers is NAT performed by the Ethernet switch ASIC, which I don't think can be fairly described as an even smaller CPU running a proprietary network stack—you might have a microcontroller-class CPU core in the switch chip, but there's a separation of control and data planes.
