[wongarsu]

It helps that in most cases when people make a zip the compression is a secondary feature. What people want 90% of the time is a container format to put multiple files or a whole folder structure into one file. .zip or .tar.gz do this just fine, even if their compression factor and speed aren't that great by modern standards.

Same with jpeg: Most people want to just encode images, reducing file size by 10% is a negligible win for most people