What it may be, if you read between the lines, they may be suggesting that more of the interested parties to get involved in development, testing (with emphasis on testing) etc. because Sangoma employees’ responsibilities don’t extend that far. Sangoma employees are primarily charged with responsibilities towards their product and that is quite understandable, and they are really good at it. It is ultimately their good will, that they give the non-Sangoma-supported modules a glance and fix them when needed.
That certain OSS modules suffer from neglect and high churn, is because of, ultimately, the ‘mode of usage’ on some of them: they are usually downloaded once, if they mostly work they are left that way, because development, testing and care for them requires mostly 3 things: time, time and more time. And certain knowledge that not everybody has. And let’s not forget, dedicated infrastructure. And (since interested parties are usually admins of certain parts of company networks) their management may also need to be involved. Who may, or may not understand, why the involvement is important or even who the hell is the open-source movement. Or may be ‘contractually bound’ to not let anything out that may help competition, even in broad sense. Or may not want to undermine Sangoma’s business model.
Bottom line ? Unless you are seriously so financially-constrained, that you really can’t afford the non-free modules, and you’re your own operator, admin and manager, and you know what you’re doing, you’d probably be easily steered towards the non-free solution, that ‘just works’.
This is not your ‘general purpose’ operating system or some libraries that everybody needs and everybody can get on board with - FreePBX is a highly specialized system; Hacking in it is not a feat of some ‘random geeks’ any more, even if it is still possible in Asterisk itself.
(Disclaimer: I am only using the Distro as a customer, running on ‘free-as-beer licenses’ where possible without compromising on features, and I fall into the mostly not-enough-time-resources-and-knowledge category when it comes to involvement in development… and so far, when support was needed, Sangoma was exceeding my expectations every time, and gone the extra mile even though I only ever actually purchased a couple of phones)