I'd also add compression time and decompression time to that list. Zip wasn't actually the best compression algorithm I remember seeing in its original days, it

I'd also add compression time and decompression time to that list. Zip wasn't actually the best compression algorithm I remember seeing in its original days, it just was the best compromise of speed of compression, extraction, and compressed size. The TOC feature was a killer because even the fastest formats decompressed slow, not to mention space was more of a premium. An additional feature that sometimes is important as well is making itself stream friendly so you can read the metadata without the entire file (or easily before streaming) as it is streamed over some context or using some technology. The landscape is much different now and so some of features you'd design into a new format didn't exist then, while others that were concerns are less concerns now. As parent hints, the compatibility alone makes zip still very desirable and actual compression is good enough given size of disks today for most people. Obviously there are exceptions.