I'm not arguing that the new products are better, just that they were evolutionarily successful. I think the issue was less one of legacy codebases, and more t

I'm not arguing that the new products are better, just that they were evolutionarily successful. I think the issue was less one of legacy codebases, and more that getting consensus on protocols and so on is _always_ slow and difficult, and that expands exponentially with complexity. And as the user-base expands, the median user's patience for that stuff drops. "What the hell is an SMTP Server and why should I care what my setting is" kind of stuff. Meanwhile the walled gardens can deliver a plug-and-play experience across authentication, identity, messaging, content, you name it. And this against a background of OS platforms (the original owners of HIGs) becoming less relevant vs Web2 property owners, and that strict content/presentation separation on the Web never really caught on (or rather, that JS single-pagers which violate those rules are cheaper and sexier). Plus a shift to mobile which has, despite Apple's efforts, never strictly enforced standards - to the extent that there's no real demand from users that apps should adhere to a particular set of rules.