I really don't believe that to be true. For our application(s) at work, the database is always the hardest part to scale and tehrefore also the biggest performance bottleneck, and the difference between good and bad SQL can be magnitudes of order of performance impact (on the query itself and locking up the DB for other queries).
Only in a "Every database has 2 TB of memory and 64 cores"-world is SQL (and database design) a negligible skill.
Only in a "Every database has 2 TB of memory and 64 cores"-world is SQL (and database design) a negligible skill.