I don't know where you get the confidence... When it comes to Protobuf, we are now at version 3 of the format. It's been around for a while, but I'm old enough to have implemented v2 parser myself... v2 is partially supported in v3, even though the support isn't documented. But, emphasis on partially. Some things are no longer there.
replySo... I'd say that your faith is unfounded. And, in general, there's no reason to believe that a commercial entity will commit to supporting any particular technology if that doesn't generate them a profit. Standard is better.
It should be noted that
reply1. Proto2 isn't actually deprecated or anything and is still widely used and supported
2. https://protobuf.dev/editions/overview/ replace and improve on the versioning concept and basically entirely remove the issue of versioning since versions and features can be incrementally enabled on a per-file and per-field basis.
aaand I guess 3: protobuf is absolutely critical to Google's profit.