Yeah I was there. It was great because it was, apparently, impossibly cheap. Then they decided to take it out of beta and jack the prices. People who were spending $10/mo suddenly had $1000/mo bill.
Never trust google.
Never trust google.
If folks want to build proprietary APIs, and people choose to use them because they are faster/better/cheaper/more suited to a particular use case, I'm not sure why that's a bad thing.
Engineering is tradeoffs, proprietary API surface is one of many things people consider.
For things like push- and email notifications, it makes more sense that a provider is involved (although APIs should probably still be open). New innovations can always start out proprietary, and the inventors can always offer support and managed infra for OSS projects.
Why? I believe the health and future innovations within the tech sector relies on healthy competition, and imo, that means that the majority of standard services have multiple providers to choose from. The only way to migrate from one provider to another is through standardized, or open, APIs. VPCs is a pretty good example of this: I can get the premium option from GCP or AWS, and have uptime, bandwidth, and choose a DC from all over the world. OTOH, I can get a cheaper, local one, depending on my needs.