What does limit you more, an OS that excludes blobs, or a vendor who provides
the blob? Surely the OS. But that's not the point in the whole freedom talk.
The point is to make all software free. Not to allow the users to use as many
devices as they want. In that respect, Windows is the freest OS available,
all devices bar none run with it. Sometimes you have to install an older
version, but Windows it still is.
Now if free software licensing (for "normal" programs and certain kinds of
firmware) would be forced through laws, which one day it hopefully will be,
then you would be able to run all devices with free software very soon.
The amount of the devices that run with a piece of software or an OS doesn't
matter for the particular freedom we try to promote here. What you can do
with the software makes it free or non-free.
And sure, we all have to limit ourselves to just a couple devices in some
areas, just in order to be able to use free software exclusively. But that
just shows that the "mission" to free all the code isn't done yet. Unethical
and simply stupid licensing is still in the majority and thus it is hard to
have a computer that allows you to run it fully in freedom. As Chris says,
the freest you can get is having a non-free BIOS and nothing else non-free.
Lemote Yeelongs don't have a non-free BIOS but they're not x86 and they don't
have a free software friendly graphicscard (it needs a blob for full
functionality) and they are very small. Not everyone's cup of tea, to say the
least.