Torrents make distribution even more dirt cheap. See sibling comment: https://news.ycombinator.com/item?id=37028576
And if you did that with a consumer ISP, they would terminate you as a customer very quickly. At which point you’ll have to pay cloud provider for traffic, or a T1 network for IP transit (alongside colocation fees and actually putting a server in a datacenter and all that).
I also have several other unmetered gigabit links. The bandwidth is out there.
And there's an issue when you consider not all content in the archive is legal (both in terms of copyright and other types of illegal), cloud providers, a lot of other hosts will probably kick you off.