Never interacted with facebook in any position, the rest is completely correct.
Google is absolutely trash at support, Apple is quite bad (in store support used to be rather good, services was always shit), Amazon is competent at least.
Amazon is also in the easiest position to offer support, since for the bulk of support queries, if all else fails, they can just absorb the cost and refund the customer. The customer is usually not any worse than when they started if they do this.
The money spent on a purchase is fungible. There is no obvious monetary refund to give to someone who can't update their app, got their YouTube channel taken down or got their Instagram handle stolen.
For the record I had a simple oauth problem flagged by Facebook and emailed with a number of humans there successfully. I'm a non enterprise/paying dev. It felt reasonably okay and quick, as if they read and listened to my responses.
Google is absolutely trash at support, Apple is quite bad (in store support used to be rather good, services was always shit), Amazon is competent at least.