I think the article's thesis is a false and misleading dichotomy.

It's absolutely true that a low friction developer experience is necessary for a database product to be successful. But this in no way implies that database internals are being commoditized or relegated to minor importance.

Snowflake is a particularly bad example as taking a clean sheet and novel approach to internals is the very fulcrum that creates the easy developer experience.

Admittedly it's been a while since I looked at vitess, but my recollection is that it's cross shard functionality is so limited as to make claiming internals no longer matter a bit dubious.

The reason there's only a handful of spanner style systems is exactly because the internals both matter and are quite daunting to get right.