I don't think the leglisation says who must provide it, but simply that it must be there.
If the PIC checks and it's not there, then there can be no flight. It doesn't matter who should have put it there. It's probably a bit like headsets. Often rental aircraft come with them, sometimes they don't but you can hire them. Often pilots prefer to bring their own.
If the aircraft doesn't come with headsets, it's probably slightly cheaper to rent.