I was going to use that exact wording in a different comment but decided against it, spooky
I mean there was clearly a lot of analysis put into aarch64 - which probably involved Apple etc - but I've seen comments previously saying they obviously got it wrong because [insert some headline design decision].
They might have got it wrong but they're definitely not amateurs at this and you can't prove anything with a one line comment.
I feel ARM could go the Docker way, who faced a similar foe in the stakeholders seeking to commoditize their core business... ruthlessly stomped on them, creating k8s, runc, registries, microvms, serverless, and what-not. Despite Docker having stellar engs working for them (and in some cases, better tech: Swarm, for instance), there's nothing they could do.
The Tencent and Apple of the world are...Tencent and Apple.
If Amazon say decided to throw billions at developing a Graviton 4 using RISC-V...they really couldn't leverage much of their previous Graviton development work. They also wouldn't have a deep bench of low level RISC-V wunderkind to bring on board to leverage the new platform. It's a chicken and egg problem.
Why would Amazon then want to pay to bootstrap a whole RISC-V market? That's a lot of CapEx without a clear potential for returns. You'll note they did develop Graviton using the ARM ISA so they didn't have to create from whole cloth a "Graviton" market.
Amazon made the same decision as PC makers in the 80s. They consolidated around the IBM clone architecture to take advantage of the rest of the market, especially Microsoft and IBM, supporting the IBM clone market. Commodore, Atari, and Apple all had to fight uphill against IBM clone market.
I haven't seen any technical advantage of RISC-V over ARM that would suggest it's worth pouring billions of development dollars into. It might make sense for Western Digital for drive controllers but not phone, tablet, PC, or server makers.
RISC-V has geopolitical advantage however in that it's not controlled by US/UK.
I can see why Amazon wouldn't pay to bootstrap that, but I can see why Tencent/Huawai/Alibaba would try to.
Now, if someone would create a RISC-V core competitive with the Arm server cores, and an ecosystem of RISC-V compatible peripherals (well, not compatible in the sense that some random peripheral would need to care about the ISA, but that Arm might not want to licenses their peripherals to a RISC-V based project?) shows up, I'm sure Amazon could do roughly the same with a hypothetical RISC-V Graviton. But if you're talking about designing a RISC-V core from scratch, that's a whole different ballgame.
This is my point. Amazon using ARM lets them tap into the huge ARM ecosystem with minimal investment on their part. The cores they're using have known qualities and meet whatever performance targets they want.
At this point RISC-V doesn't have that same ecosystem. It doesn't even have extant high performance cores someone can just order. Building momentum is expensive. If selling that ecosystem isn't your main business it's probably not worth investing millions or billions to develop it.