There is a difference between maintaining MySQL servers and the underlying operating system and writing efficient queries, optimizing indexes, knowing how to design a normalized table and knowing when to denormalize, looking at the logs to see which queries are performing slowly etc. using AWS doesn’t absolve you from knowing how to use AWS.

There is no value add in the “undifferentiated heavy lifting”. It is not a companies competitive advantage to know how to do the grunt work of server administration - unless it is. Of course Dropbox or Backblaze have to optimize their low profit margin storage business.