It's fine for people who administer their whole stack themselves, but companies like Red Hat don't seem to be on board yet (their website only mentions embedded applications as far as I can see). Compiling open source software against a platform is the easy part; most places don't want to deploy their own build of Apache. Intel has also spent considerable resources contributing patches and optimizing compilers for their platform. If AMD wants to move large clients off x64, they can't just say 'Well, look, Perl compiles'. They need consulting shops onboard, they need large, well-tested repositories of Linux packages.
Debian, Ubuntu, and several other distros have ARM builds. It's not a matter of saying, "Oh, you can compile it yourself." It's just a matter of saying, "Use one of these extremely popular distributions."
Fedora is available for ARM, which means RHEL and CentOS almost certainly aren't far behind. There's also a port of RHEL to ARM called Red Sleeve, which means most of the hard work of a port has already been done. Given that the potential cost savings are pretty big in a large data center, I suspect we'll start seeing deployments pretty soon, and the pressure on Red Hat to provide ARM will grow.
I'm not really arguing with you, per se. There are plenty of people who won't make the jump until Red Hat does. But, there are plenty of people who take their cues from other providers.
Gentoo has always been aggressively multiplatform. I know there are other distros which run on ARM as well, but I don't know how clean their solutions are.
Anyway, hardware availability is an important prerequisite. Sure everything mobile uses ARM, so the Linux kernel is in good shape. But once there's cheap server hardware available, more work will be done on the distros.
