It's a lot of work and money to maintain and it's essentially duplicating/splitting the metacpan efforts in term of functionality. I think users are starting to vote with their feet as well so it's just better to do this earlier than later.

I was always grateful for search.cpan until metacpan got out of "beta." At this point search.cpan is just an irritant; being the first link(s) in search results. Personally, I'll be happy to see it out of the mix. I have not used it intentionally in years at this point.

I hope they remember to add a permanent redirect.