Probably because you're missing the point?
See: https://www.fourmilab.ch/documents/digital-imprimatur/ (prescient and very depressing read, but read it anyway if you haven't done so).
UPNP and some other firewall traversal tricks restored some of that but asymmetric bandwidth is the norm these days. Maybe with IPv6 we'll see a reversal of these trends.
edit - not crapping on dropbox particularly. Lots of things should be basic functionality by this point, sharing files being one of them. If stuff was more like plan9, for instance, things like skype wouldn't exist either.
This is the is-ought problem, or hume's guillotine.