I don't know if money is an issue but the way you talk about servers from 2012I can't help thinking that.
Sooooooooo. I want to suggest you start doing a subscription payment model or maybe a machine limit. Personally I've used my Sublime license on about 7 different companies machines as well as 4 of my personal machines. I've always felt guilty about the sheer amount of use I've had out of them.
Maybe you could get inspiration from an obscure search engine scraping app that has a VERY strong per-machine license system. Its called Scrapebox. Easy to find.
Maybe you could start limiting it a bit and/or releasing business licenses.
I don't know - I'm throwing ideas out there because I feel I've had more service out of my license than seems fair and I think you deserve more money for the app.
Maybe even just make the trial a bit tougher/annoying to compel people tto buy?
I dunno - just a thought.