I apologize for what is certainly an off-topic rant, but:
Why not use gzip for all?
gzip doesn't compress as well as lzip.
But gzip compresses well enough, and storage is almost infinitely cheap.
Also, the benefits of switching to a better compression algorithm need to be weighed against the maintenance hassle of adapting to the switch.
Absolutely. And that hassle is HUGE. Every few years, I have to replace my monitor, after putting my fist through it out of frustrated rage, because I've just downloaded some package I'm interested in, but first I have to go through the yak-shaving exercise of downloading and building a decompressor for the nifty new "better" decompression algorithm it uses. (I'm kidding about the broken monitor part, but just barely.) But, clearly, I'm just a cranky old Luddite. Progress marches on. Please, let's not clutter this list with a bunch of zealous endorsements of how Very Much Better the latest compression algorithms are, and how stubborn I am for failing to appreciate them.