If one of the primary points of open source software is to promote accessibility, Reaper goes a long way towards this without actually being open source. There is no DRM, there is no need to make an account and do some long sign up process to get Reaper up and running, there is no iLok required (vomits in mouth a little). You can download it in and start working on a project as quickly as your computer can finish installing it.
From Reaper's license popup:
> We are showing this message, instead of crippling this evaluation version of REAPER, because we do not feel technological enforcement of licensing policy is in the best interest of our customers
Reaper is the only professional artistic software (sold as a product) I have ever come across that is remotely realistic about how people use it. Nobody has ever pirated Reaper in the history of Reaper, there is no point and that is how software should work in a more sane world.
Further, 99% of digital audio workstation customers start off as broke kids with no money to feasibly drop on a music production software that costs $150 or more. So a huge amount of future paying DAW customers are piracy converts anyways. Making a DAW that can't be pirated is a sure way to shove your future customer base onto somebody else's DAW that can.