I agree with your point(s) but specific to this: > Can someone name me an instance where a site as popular as Twitter eventually flopped because it didn't play

I agree with your point(s) but specific to this: > Can someone name me an instance where a site as popular as Twitter eventually flopped because it didn't play nicely with third-party developers? The internet is still very new, the internet in its current form is even newer. Facebook is ~8 years old, Twitter is ~6 years old, it's probably not even worth considering previous examples of social sites and developers because even Twitter in 2010 and Twitter now is significantly different (as a company, product and community).