It's not really a monoculture when there are 4 separately developed rendering engines. IE isn't going away thanks to corporate users, Firefox is still going strong although nowhere near where it was, Apple have a strong market position that will not go anywhere in the near future and Google has forked Webkit to go their own way so I can't see any single browser dominance any time in the near future and I certainly haven't come across a single site that insists I use a particular browser like used to happen in the bad old days of IE5 and 6.
I'll have to investigate the apps issue further because I'm not happy with them saying where I can install apps from. They don't do it on Android so why should they do it on Chrome.
I'm not defending Google here by the way but people's fears of a return to the early 2000s IE only nightmare seem largely unfounded to me. Google have contributed a number of technologies to everyone - a long way from the One Microsoft Way of yesteryear.