This is almost certainly why they also don't offer smaller paid accounts (like 10-20GB) -- they know users of such tiers will probably keep their accounts maxed

This is almost certainly why they also don't offer smaller paid accounts (like 10-20GB) -- they know users of such tiers will probably keep their accounts maxed out. I know I almost always utilize nearly 100% of my 2GB free account, and I'd probably do the same with 10GB.