RISC-V the ISA is open; RISC-V implementations need not be. There's no reason to believe that any truly high-performance implementations will be usefully open.
While achieving an open-core design comparable to Zen 5 is unlikely in the near term, a sustained open-source collaborative effort could, in the long run, significantly change the situation. For example, current versions of XiangShan are targeting ~20 SPECint 2006/GHz (early where at ~9).
Stuff tends to stay open until a new leader emerges. Then the closed source shell appears.
We've seen this with the hyperscalers and in a million other places.
Use open to pressure and weed out incumbents and market leaders. Then you're free to do whatever.
So we'd be replacing NSA spying with MSS spying.
That's why this is geopolitical.
The DoD and Five Eyes prefer ARM, where the US maintains a strong lead.