Is it even worth talking about speed without at least considering client network conditions? A lot of people have poor internet connections, many places world-over are basically mobile-internet only already, shared internet spaces with variable QoS (campuses), etc etc. Most people aren't using engineer-priced laptops/workstations or backed by enterprise-grade routing equipment, after all.

If I understand Tor correctly, last mile connectivity is not a bottleneck.

You are correct. Tor's speed has nothing to do with your local rig or network. Unless you're on an abacus.

Yes it is. I can't speak for everyone, but in Brazil, it's virtually impossible to use Tor even for HTML-only websites. And I can say most people have a slower bandwidth than I.