I guess any 74xx chip can contain an SoC running a complete OS, and in the case of RAM be able to read and write anything it wants and phone home about it. But

I guess any 74xx chip can contain an SoC running a complete OS, and in the case of RAM be able to read and write anything it wants and phone home about it. But it would be very conspicuous when a chip that should only contain a handful of transistors or a simple grid pattern of memory cells is decapped. They are far more auditable than anything VLSI. It's true that the battle can't be won, but that means it's a war of attrition. Backdooring 74xx chips would be very inconvenient and expensive compared to just pushing some code into the Intel ME or AMD PSP. The flip side of that is that building and using a 74xx computer is going to be just as inconvenient and expensive for the user. So this is more of a fun thought experiment than a serious solution.