Earlier quoted context omitted.
C'mon, databases are great but they are not in any way a "deep tech" field. Databases exist today in a zillion production forms as commercial products and free software. Deep tech includes things like nuclear fusion, solid state batteries, quantum computers. I know everyone wants to feel cool, but just because your new javascript framework will be in beta for the next ten years doesn't make it "deep tech".
I'd ascribe "deep tech" to anything that you can reasonably get a PhD in and have it not be unusual. There are dozens of academic conferences on DBs pushing the frontier forward.
The dude doesn't know anything about databases.