I think OP is missing the point. Browsers of today are taking over the space which Java tried to capture (remember "write once run everywhere" slogan?) but failed. They provide (mostly) unified development platform. But the catch is that unification comes as a direct result of the fact that they are meant to be something else. Any other unified platform faces an uphill battle while browsers are... just there. Are they perfect as a development platform? Hell no. But in absence of every other option, well... we take what we can get.