Even 5% is uncomfortably high if you're planning to build your mission-critical infrastructure around it.
And lets be clear, this is not a catastrophic risk; your contract with GCP guarantees they will not discontinue services without 12 months of notice so you will have time to do an orderly migration unless Alphabet itself goes under.
I am a GCP user; I have found their offering (actually having GPU quota) significantly better than the other clouds and GCP shutting down does not keep me up at all.
12 months is the time for the contracts to settle between these enterprises and cloud-vendors.
If you work at a company that can't do a cloud infra migration in 36 months, I don't have any good advice for you, but I doubt most commenters on here fall into that bucket. Frankly, I would expect companies that large to be in all the clouds so that you could negotiate them against each other, but I doubt that impacts many people here, and the chance of any of these worst case scenarios happening is vanishingly small.
Some companies even need to check with the laws they reside in if the new cloud vendor can even be used.
Just work in any financial, medical, pharmaceutical, government-related... company and you'll understand that a year is nothing for these companies.