If we were healthy as an industry in ways that we are clearly not, we would see this coming-together as an opportunity to become more efficient. We'd be looking for opportunities to factor redundancy from our platforms, for example reducing our reliance on CSS and HTML, and perhaps eliminating the need for server code. These are serious possibilities. There isn't much functionality left that must be on the server. If we concentrated real hard, we could make those go away.
But the BigCo's seem to want the chaos? And as a result they'll need lots more programmers to maintain all the incompatible stacks. I don't think this is driven by business needs, rather it's programmers trying to be sure they continue to have jobs. Re-inventing stuff that already works pretty well. Job security.