You're right, it is kind of disappointing. I think the fact that it would cost so much to come up with something novel and then optimise it to the point that conventional CPUs are at that it seems hardly worth the expenditure. The next major frontier in CPU design would appear to be in materials and manufacturing rather than architecture - although no doubt whatever the post-silicon world looks like will influence future architecture substantially.
Mind you, if nothing beyond the smallest silicon processes turns out to be practical then we might see attention turning back to re-thinking CPU architecture, but until then I think a lot of money will be spent looking at materials and manufacturing over interesting ISAs.
Although the possibilities are arguably greater for new designs to get traction today.
There are a lot of reasons. Open source, cloud providers, etc. But a big one is that you can't just depend on CMOS process shrinks to make processors faster. Therefore, your new design isn't necessarily going to be eclipsed by whatever new x86 CPU comes out in 12 months.
That's true, but the difficulty is it's not just going to take 12 months to do something like this. A radically new architecture would take years to become competitive with today's processors for all of the use cases that would make it marketable. Meanwhile the x86 guys aren't just going to sit still, there's almost certainly more IPC to squeeze and they can add fixed function hardware (as they've already done for video encoding/decoding) or FPGA area in new product ranges and keep building new markets that way.
An instruction to insert into a queue on another core would be a great thing. The T3E had it, InfiniPath / OmniPath has it between boxes, and I've heard of a research project that did it on a modern cpu.
Mind you, if nothing beyond the smallest silicon processes turns out to be practical then we might see attention turning back to re-thinking CPU architecture, but until then I think a lot of money will be spent looking at materials and manufacturing over interesting ISAs.