[Retra]

My point is that you don't build indexes for every query. You build it for the important queries, and you let the user tell you which queries are important, rather than which indexes to build.

Because honestly, the only reason any user cares that an index exists is if they need it for performance. It should be an implementation detail. Something better than an index might come along, and we've all got to run victorian-age schemas because we've written "create index" all over the place.