[krylon]

> With more and more going into the browser & cloud, how much is really left on the client side to be backwards compatable with these days?

For desktops/laptops and mobile phones, this may be true. For embedded device (where a lot of ARM chips end up) it is not an option, usually.

Likewise, on Windows, there is a huge amount of third-party software that is, for better or worse, tied to the CPU architecture. And for a fair amount of that software, vendors are either unwilling to port it to a new CPU or have stopped supporting the software altogether (or have gone out of business). Consider the sad fate of Windows RT. Windows on low-end ARM devices might have been sweet (as far as Windows goes), but if the only piece of software it runs is IE/Edge and Office, it is not terribly useful.