I was under the impression that for process nodes you would reasonably use for small smart appliances the fab cost is too high, and certainly not high enough that nobody would pick up the tab if the gadget makers would start to require open IP for their IoT / smart appliance offerings.

There are, and have been a few CPU/MCU upstarts that have actually done shorter runs of silicon, and while they are usually quite well funded, the numbers doesn't seem to be prohibitive at all.

If the need was there for it NOW, fabbing something with existing open ip is quite likely to be 'free money' (or free market share), as the semiconductor industry appears to be entrenched with ip licensing so much that I sincerely doubt that they would be quick to follow suit. If only because any open offering from them would be seen as detrimental to market dominance, and lower the value of ip cross licensing deals.

Unfortunately I don't think the market need is there, and won't be for quite some time. I would love to be wrong though.