2647 connections per server per second is pretty abysmal for modern server hardware, especially if you had to rely on a whole bunch of caching front-end complication and proxy web servers to make it happen.
You can't say that without knowing what the app does.
A recent project that I've been involved with switch from Java to Ruby and they reduced the number of servers by 10 times (!). But I don't blame Java, I blame the programmers of the last code base. You can write unmaintainable messes in any language.
I once interviewed a Rails developer who was bragging about a Java-to-Ruby conversion he'd worked on. He was proud that they went from 50 servers running the Java system to only 30 for the Ruby one.
Upon further questioning, he admitted that those 50 servers used by the Java system were from 2003, and the ones powering the Ruby-based system were from 2011! They didn't even halve the number of servers required, but the new servers were many, many times more powerful than the old ones.
