I doubt too many people forgo learning SQL exclusively because they are too busy learning other, higher priority things. Most people have free time and still choose not to learn SQL. I had a teacher in highschool who referred to not doing things because they weren't really that important as being "legitimately lazy" which I feel is an apt description.
It's just that there's so much more exciting stuff to learn, like machine learning, game programming, latest shiny web framework of the month.
If you're a person who likes being visually stimulated while learning, spending free time outside of work to learn how to query tables and design schemas is about as exciting as watching paint dry.
