There are plenty of sides to this:
- The technical side - Is it actually a better designed or more capable ISA than others?
- The legal side - Licensing, patents, ownership
- The money-go-round - Who pays money to who for what. How money is made.
- Is having a common, open ISA platform that anybody can implement actually good for the tech industry?
On the technical side, I think it is a better core ISA than x86. It still isn't fully formed (with some extensions in flux), but what is there is arguably technically better - no "real mode", no super-complex instructions to gum everything up. Also the ISA is a lot more approachable than other ISAs.
On the legal side, having an unencumbered ISA is great. If you win the lottery and want to set up "GaAsSix", which sells high performance solutions can competes with SiFive you can. And if your IP vendor is yanking your chain you have options. It then focuses on who can provide the best value to their customers, not who has owns what IP.
Is having a common, open ISA good? I think so. Even if it is just so we don't have just x86 for big systems and ARM for smaller systems.
The money-go-round is the most confused story at the moment. I really don't think you deliver ARM-like levels of products, support and documentation without an ARM-level licensing revenue stream to pay for your efforts. The question is how much lower can you deliver and still have a viable, sustainable product to the market.