I don't know if it's ever been a core skill. You can ask any dev. Many tell me SQL is not something they use every day, so even if they learned it, they usually forget it in no time.

SQL is burned into my muscle memory because I work on ML models with large datasets. It took me a lot of trial and error to get decent at SQL. I imagine most devs just don't have the reps because their work rarely exposes them to SQL.