I think Canonical does a great job supporting the ecosystem by providing a
lot of resources even though they really haven't made money on Ubuntu yet and
is still Shuttleworth's money. They also got the support of companies and
universities to mirror their packages all over the US which is nice.
I've tried Debian before and keep coming back to the Ubuntu based ones due to
the level of polish with an Ubuntu release not only in the LTS but also in
the 6 month releases. I also like that they have a dedicated server edition
(which I use) and the wealth of packages on launchpad.
I know Red Hat gets a lot of money for the commercial support of their OS,
but Canonical is another company that is pretty serious about it as well.
So like you said, without Red Hat, IBM, Oracle, and Canonical, there would be
no Trisquel and we should be thankful that these big companies are willing to
take Linux seriously.