You're comparing apples to oranges. Typing is much harder to relearn due to muscle memory. New well designed programming languages become quite popular quickly and go viral when they solve the right problems for developers.
SQL is a very sound querying language originally based on relational algebra and tuple relational calculus. Many attempts have been made in the past to come up with better syntax but they don't go far which might have to do with the fact that authors realize later that SQL is just a thin layer masquerading the mathematical concepts required to retrieve relational data and make certain assumptions without breaking set theory axioms.
One common mistake I see is that developers attempting to create an SQL replacement often approach it in the same mindset as creating yet another general purpose programming language.
Edit: The above is not in reference to PRQL. It's just my anecdotal experience working on several SQL engines, building ones from scratch and working in this domain for 15 yrs.