Sure, if you're learning SQL or a technology to market yourself, Oracle DB might not be the best time investment. However, if you're already an expert in that, you shouldn't have trouble finding a role somewhere.
Doesn't look like it to me.
https://www.macrotrends.net/stocks/charts/ORCL/oracle/revenu...
https://www.thomsondata.com/customer-base/oracle.php
That doesn't even include primarily government contract companies.
I'm not sure how correct that is either, but it's incorrect to call it a legacy skillset on an unpopular technology. A good number of those new companies, if successful, get acquired and are forced to integrate if not convert to Oracle.
The world is way bigger than SV.
From my experience across some MSSQL server, oracle, sqlite, and some non-professional postgres, the given database model trumps the underlying database tech when dealing with pains writing analytics reports. There are many options to mess up a model design or for feature extension to turn the model ugly.
Forget about building a new company on an oracle stack, the cost is prohibitive. The open source rdbms are very good and cloud providers have chosen their champions. But for a large legacy corporation with expensive, sensitive data, oracle makes sense. To an extent with a well trained dba the db is “self-documented”
Lol sometimes dbs aren’t exclusively used as a global web app backend for ultra scaling grocery delivery services or whatever. Sometimes db models persist for years and you need assurance that this tech is archival quality.
An aside, I think it’s funny the link you shared is a php site, another dinosaur!