tbf some of these products are simple features like the youtube stories one, if you made a similar list for a large web company (like Meta), that list might just be as big
I don't understand why anyone trusts anyone. If you build your business on anyone else's back, then you have to be ready for them to disappear at any time.
That being said, if the choice is between building on Google or JonathansAwesomeSoftwareCompany, then I'm picking Google every day of the week. Google may kill the project, but they are infinitely more likely to remain solvent and be able to throw resources at what I care about than Jonathan is.
Not the biggest Google fan, but this page presents only one side of the picture. Google has some solid services that have been going on for a long time.
Additionally, a personal opinion: They are relatively better than Microsoft/Apple/Amazon.