Earlier quoted context omitted.
The ecosystem. That's its main selling point.
Thanks - for servers? Would this be used to host a database?
https://research.cs.wisc.edu/multifacet/papers/ieeemicro16_c...
It not the ISA that makes it desirable. It's all the tooling, apps, branding, and talent around it. You have to rebuild that stuff for new ISA's. You also have to get the market to trust a new one after so many perished. That is why companies pay ARM $1-15 million for licenses to use that ISA and brand name.