In the old days, we could see a 4K IPv4 stack. But, v6 has pushed to simplify the router code by pushing protocol code into the endpoint. Router discovery, neighbor discovery, multicast (v6 doesn't do broadcast) have all been pushed to the end device. This takes a lot of RAM. So, we'll have to go to larger processors to make it function.
As for the Hackenstein period, it will likely start to taper off as legacy units get replaced due to attrition. The silicon manufacturers can't make much money on 8051s, they're driving the customers up the processor scale so the silicon folks can turn a profit.