I don't know. I think Pluton is going to be a temporary thing until the alternatives are more mature.
OpenTitan is a great option but it'll be at least another 2 or 3 years before it truly stabilizes and has at least some amount of battletesting in ARM chips as a secure enclave.
Alternatively they may go with Caliptra as they've been involved in its development for a long time however it is a less mature option and it's not as flexible of a secure environment as OpenTitan is.
The FOSS secure enclaves have a lot of heavy investment but it looks like the AI boom happened earlier than anyone really anticipated and Microsoft jumped the gun and demanded their SE environment because the other offerings weren't mature enough.
OpenTitan is a great option but it'll be at least another 2 or 3 years before it truly stabilizes and has at least some amount of battletesting in ARM chips as a secure enclave.
Alternatively they may go with Caliptra as they've been involved in its development for a long time however it is a less mature option and it's not as flexible of a secure environment as OpenTitan is.
The FOSS secure enclaves have a lot of heavy investment but it looks like the AI boom happened earlier than anyone really anticipated and Microsoft jumped the gun and demanded their SE environment because the other offerings weren't mature enough.