Getting set up in AWS in a remotely manageable way is in no way "immediate" - a lot of my income came from that fact (and another large chunk came from fixing setups that had descended into total chaos because people "just" started spinning up resources without properly managing it)

If you want ad hoc rapid setup you can get a managed server up and running about the same time as an instance with AWS too, from a provider that also offers colos and cloud so you can pick and choose and move between the three depending on what is most cost effective for specific needs. In practice, ironically, having that option makes cloud instances even less cost-effective because having the option of spinning up cloud instances an tie them into your environment means your can allow yourself to have less spare capacity on your managed/colo servers.

Or they're not aware of the options. AWS has massive marketing and market share. A lot of businesses aren't even aware of AWS savings plans and spot instances. That's even why there are companies that purely offer to optimise "cloud costs" as their core business.