Personal experience: I have to support an internal tool for a company in app engine. The contract is part time and I have to prioritize what issues to fix. The answer is usually "those caused by Google deprecating something". The nosql db some hyped individual has chosen years ago - "deprecated, we don't bother with solving bugs there". Email service: "it is in python2, but not in python3, look for management approval to use external service". File storage: "this library is deprecated, use whatever service is fancy now". Task queues: "nope, we are changing the api and calling it cloud tasks now, so please refactor all of your files to use the new semantics".

The list goes on and on.