There is no comparable alternative to the Internet Archive though. They've gotten involved in several lawsuits and their future is far from guaranteed. They're an incredibly important organization, but I think it's too important of a project to be limited to one organization, or even one country or region of the earth. A solar flare could destroy a lot of history.

I don't know that the economics of having multiple Internet Archive-like organizations is currently feasible (I imagine getting funding for one of them is hard enough), but even a partial offline mirror hosted someplace else would be nice. Maybe to save space they could take the oldest version of a page, the newest, and the midmost version timewise, discarding all other versions. They could also heavily compress images, video and audio to save storage space (would increase processing costs, but if willing to throw out quality, could compress quickly and still save a bunch of space. E.g. downscale all videos to 480p and use veryfast preset and CRF 28 with ffmpeg. Even 240p is a lot better than nothing. A pixelated form of history is better than no history.)