All the commercial enterprise database performance consultants are busy spending the money they make from fixing these critical apps and expensive problems ;-)
Edit: Can’t speak much for MSSQL and DB2, but there are lots of similar problems in the Oracle world too, sometimes due to an app design that works against the intended use of the DB/optimizer, sometimes due to a database optimizer bug and sometimes just due to the complexity of estimating the optimal plan based on limited statistical summaries of the “shape of your data” and expectation that the optimization won’t take longer than a few milliseconds.
I regularly fight bad execution plan problems like that on Oracle (more often than not after minor upgrades). And yes you can read about problems like that looking at the documented incidents on the Oracle support site.
And no, hints are not always the solution. Sometimes they even are the culprit.
If I had a wish for Postgres, I'd rather have something like SQL profiles (or similar) where you can register an alternative plan with an existing query, not hints. Very often a full deployment in order to change a single SQL isn't an option.
Selection bias. You don't read many stories about them in general. I can't remember the last time DB2 hit hn front page for any reason. Search shows most of them are 7+ years old and the most recent is "Db2, where are you? Big Blue is oddly reluctant to discuss recent enhancements to its flagship database"
