It's a cycle tho - they don't need it because the developers of software can't write to the newer standards since the hosts won't support it.
Plesk 8.01 supports php5+, at least on my webhost. Getting mysql to 5+ hasn't been quite as easy, but I'm working on it - we need to promote those good hosts who will support it and move away from those who won't - money will pull them to our side or they'll go the way of dial-up net service and be relegated to second/third-class status
