The garbage collector is something you should not think about when programming and most programmers don't even need to know it exists. You only think about it when you need to seriously optimize things.
For SQL it's a bad design choice because of what SQL is and what SQL is targeting.
SQL is a high level abstraction that automatically determines a query plan based off of high level input. The problem here is that it can choose a bad query plan. So you need to "hack" the query in order to trick the query planner into doing what you want.
It's also targeting the slowest part of the stack: Non volatile memory and IO. The slowest part of the stack should be targeted with a zero cost abstractions to maintain speed while the fastest part of the stack you can use a language like python for your web app it's fine because databases are magnitudes slower.
