I sincerely hope that if they come up with a 128bit instruction set they call it "x80" to maintain backwards compatibility with previous set names and be deliberately confusing to everyone.

AMD and Intel are well-matched competitors right now except for AMD having some money.

"When we step back and look at it, we see that it is a de facto open ecosystem. Open ecosystems benefit from having consortiums with stakeholders, all with a voice in driving the ecosystem forward"

Lol if the x86 ISA is an open ecosystem, CocaCola is an open source beverage.
Trying to read between the lines though, is Norrod implying that they are considering moving toward a more open x86?
The impression I'm getting is that they're thinking about sacrificing various legacy features (32bit being the most obvs one) to bring performance per Watt closer to the competition. And then put in its place a more standardized successor? RIS86? They will likely aim to steer clear of formal (published) standards because they want their trade secrets. However, they will need to simultaneously ensure not to violate antitrust rules.
Might be easier for them to just forfeit trade secrets and embrace a different model altogether.

I would imagine that any x64 binary compiled to work with both chipsets would only use the instructions that are common between them. This would mean there's not much gain in developing a new insutruction unless both companies support it.

I'm sure there's some super-optimised stuff out there that targets extra instructions when they're available, but it's very rare.

Go RISC-V!

enemies are joining forces against a common enemy: ARM

Aren't they legally required to be, or face monopoly litigation