These days, no one gets fired for choosing AWS, and people get hired for knowing how to work with AWS.
Instead of you paying IBM to run your "mainframe" infrastructure, you pay AWS to run your "cloud" infrastructure. It's the same kind of service, with the same kind of economics, but under a different guise. AWS even offers an "on-premises cloud" solution for large customers.
As was the case with IBM at its peak, once you start using AWS's alphabet soup of ancillary services that work only on AWS, switching away from AWS becomes about as easy and enjoyable as replacing all the plumbing in a skyscraper.
Azure is the main alternative. There's always a #2.