Your post contains two distinctive arguments: paying premium for managed services instead of learning a thing or two, and paying AWS for their services.
Re first argument: I don't know how to implement DDoS protection, neither is my company a DDoS protection shop. Should I learn how to do it myself, or pay CloudFlare to do it for me? What about S3? What about Aurora/Dynamo/SQS? Where is the line between "your company TOTALLY has to do it on its own" vs "pay the people who know how to run X to run it for you"?
Regarding AWS prices: it's not like you are forced to use AWS. Use the cloud your team is most familiar with. I'm not an expert on cloud offerings, yet if your problem is $20k/month and $15k/month infrastracture costs, you might be solving a wrong problem.