My guess is it'll be IBM.

Based upon some research into numbers...

They'll absorb the talent. Expand IBMs offering of Vault-ish product while basically reselling Vault as a line item addition to their existing line items.

Less pain for IBM from license drama and the selling of open source Vault with an IBM tweak to a MUCH larger user base with zero sales expense.

IBM gets all Vault talent Hashi gets massive market without sales

Hashi is $800MM revenue because of 80% sales and marketing.