While it's true that you can't always compare open source support with vendor support, I definitely feel the tide turning on this one. In the past 2 years or so (and this is just my experience, YMMV) I've found it much easier to get changes made from a project maintainer, than from most software vendors.

Github has changed this drastically. I can fork projects, fix things myself, send pull request back to the project maintainer all in less time than it usually takes for a traditional software vendor to even put my support request in the queue and acknowledge the problem.

I'm just saying, things are changing. Your business will have to change too if you want to sell to developers. You can't keep repeating the same aphorisms about support and technical costs.