I think that now the Joomla marketplace as such has matured a lot & there are lots of developers from all over the world that can offer their services for Joomla Development.

Even our company specializes in Joomla based Development & overall 80% or so of the business is Joomla. So i'd say Joomla Development is definitely a requirement & it does come much cheaper than developing things ground up.

And all our open source support & development & free extensions are supported by such commercial projects .

There are also a lot of people who will sponsor projects which can be released to the community.