You can just as effectively have HTTP sites that are simple listings of available software. I don't think FTP removal is really relevant here except for nostalgia.
FlashFXP was a popular client that supported this: https://en.wikipedia.org/wiki/FlashFXP
The advantage with HTTP wasn't efficiency, it was that resuming interrupted downloads was typically possible with FTP but not HTTP (because ranged GET took a long while to get support in both servers and clients).
They went to shit, but didn't start out that way until they started to try and fund their site through a shit ton of ads.
That was a dark day for the internet. Thank goodness for ad blockers.
Still - at least Tucows left up their mia-culpa (entitled "Tucows Cuts the Crap") https://tucows.com/blog/2016/05/03/tucows-cuts-the-crap/