They're a nonprofit - so they can't be acquired like a typical for-profit company. They could in theory sell some assets but it'd be very convoluted if they were the core assets -- per US tax law, nonprofit assets must remain in the nonprofit world, so there's no risk of any tech company ruining them.
I heard similar things about another American nonprofit and now I'm not so sure about it. When money and will comes along, loopholes come as well.
So, I wouldn't be so sure, unfortunately.
Look at OpenAI - where there’s a will (and an army of lawyers), there’s a way. That said, I don’t think any of the big tech orgs would be interested in acquiring them. Google and Amazon even already have their own public CAs that are in the major trust stores.