But what is FB's "ecosystem"? Is it just their current users? Or is it all their potential users, including those who do not yet use FB at all? I think FB believes that it's the latter, and that it can capture the most value from all those potential users by exerting tight control over the FB user experience.
More precisely, I think FB believes that the costs of exerting tight control over the FB user experience (i.e., the discontent it causes among some fraction of existing users) are far outweighed by the benefits of capturing as many potential users as possible and making them stay within the FB walled garden. To capture new users, the UI doesn't have to be good; it just has to be good enough, and "good enough" to someone who hasn't yet used FB at all is a low bar.
The real test will come when the market saturates and the above reasoning no longer applies. Based on what other companies in similar positions have done in the past (with Microsoft being the #1 example), I don't expect FB to loosen control very much, and to the extent they do, it will be, as I said in another post in this thread, more to allow third party developers to do market research for them than anything else. But we'll see.
Citation needed.
Also, this is a false dichotomy. Nobody is splashing patchouli on their tie-dyes before marching on Menlo Park to demand that Facebook's servers be liberated for the masses.
The only dispute here is whether Facebook's short-term fixation on control is bad for the long-term health of their ecosystem, which is by far the company's largest asset.