Will mention one more thing. The desktops/laptops are compatible with free
software distributions like Parabola GNU/Linux-libre and Trisquel. No matter
what system you get you will have some pieces of non-free code. There are
pieces of non-free code hidden in keyboards, hard drives, and elsewhere. The
BIOS is just one component that is a problem. As was pointed out coreboot
isn't necessarily 100% free with all systems its loaded on.
The solution to this problem is focusing resources. Randomly purchasing
hardware doesn't create any incentive to develop free software or push for
the release of free software from companies upstream, or provide for the
resources for any company to move barriers. As it is random purchases of
hardware simply further entrench companies which are already dominate, and
don't care about free software.
Nobody is going to listen to one individual, nobody is going to listen to a
small company, but combine those individuals and a single large company can
create an impact. Right now there are lots of individual all demanding free
software, but nobody is listening, as individuals are too small to be
noticed. You have to create a roar for change to happen. Show them there is
money by merging resources and there will be a company that can impact
change.