Can you explain the thought process with regards to why it's okay for you to receive compensation for your efforts, but not the OSS developer who invested significantly more time (nine years, in the case of Redis) in creating the product?
What will you do as a technology practitioner if more projects move to this model to provide some semblance of financial support for their devs? Write your own RDBMS? Your own in-memory caches? I won't discount these paths as impossible, but it increases your costs and time to market significantly.
Standing on the shoulder of giants is both efficient and convenient when building your product/stack by bolting together existing tooling (what products aren't using Redis/Memcached, MySQL/MariaDB/Postgresql, ElasticSearch, etc), but it should have a cost; those shoulders aren't free, and it's not reasonable that those enjoying easy revenue (AWS, for example) by providing managed services with these tools don't have to share that revenue. You can't freeload forever.