The interest is BECAUSE it's well explored territory. The concept is proven and works fine.

On the low end where RISC-V currently lives, simplicity is a virtue.

On the high end, RISC isn't inherently bad; it just couldn't keep up on with the massive R&D investment on the x86 side. It can go fast if you sink some money into it like Apple, Qualcomm, etc have done with ARM.