It's a good point, but you also don't keep your ratio, if you stop seeding and only leech, eventually your ratio gets bad again. You just changed to prepaid volume instead of subscription :D

But yeah, you also don't need your usenet access forever. It's only for rarely found stuff, remember? You just accumulate those over some time, then pay for a month to get it all, then cancel again. Main tool is public torrents.