It does? I wouldn't waste my money with a host that was unable to
provide PHP 5 support, at least in some way. I think the "it will
break lots of scripts" is a cop-out. There are various ways to allow
both on one server. Assuming they're technically proficient enough of
course.
'What is the best way to get to get to Detroit from here?'
'You don't need to go to Detroit. It's cold in there. San-Francisco is much better.'
Do you see the problem here? You're not adressing the issue I spoke about.
Issue: I think BC slows down the evolution of the language. I know for sure it makes some people less willing to upgrade. And there are ways of avoding unnecessary BC maintenance altogether.