HTML5 support doesn't suck. Check out http://caniuse.com, and you'll notice that non-IE browsers are doing a rockin' job supporting HTML5. If you develop for iOS or Android, HTML5/CSS3 has been a joy. Sure, there are hiccups, but support is far from "sucking".

It sounds like your companies upgrade policies suck! OR, their decision to support/build around proprietary web technologies, hindering their ability TO upgrade. That sucks.