Comment by mike_hearn

Use of underpowered databases and abstractions that don't eliminate round-trips is a big one. The hardware is fast but apps take seconds to load because on the backend there's a lot of round-trips to the DB and back, and the query mix is unoptimized because there are no DBAs anymore.

It's the sort of thing that can be handled via better libraries, if people use them. Instead of Hibernate use a mapper like Micronaut Data. Turn on roundtrip diagnostics in your JDBC driver, look for places where they can be eliminated by using stored procedures. Have someone whose job is to look out for slow queries and optimize them, or pay for a commercial DB that can do that by itself. Also: use a database that lets you pipeline queries on a connection and receive the results asynchronously, along with server languages that make it easy to exploit that for additional latency wins.