Yes, I realize that the 4800X is not meant for consumers, and said as much in my post. My point is that there doesn't seem to be any technical limitation that would prevent a consumer grade Optane based SSD from working with non Kaby Lake CPU. It all depends on what Intel decides to with the technology when it releases a consumer grade product similar to the 4800X. Maybe you'll be able to use it just like any other PCIe SSD, or maybe Intel will artificially limit its compatibility.
If the OP was referring specifically to "Optane Memory" caching drives (i.e. this: https://www.amazon.com/Intel-Optane-Memory-Module-MEMPEK1W016GAXT/dp/B06XSMTN31?tag=bom_tomshardware-20&ascsubtag=site:thus|tid:65511494872096167), then those only work on Kaby Lake CPUs/200 series mobos. If the OP was referring to Optane based products in general, then I believe there's some hope that there will eventually be products that work on other platforms.