Why can't I find a tent that fits in my pack?

A: Who knows? Could be force of habit, something to do with fabric dimensions or maybe the best size for efficient shipping. I guess I never gave it all that much thought as typically I lash the tent to the outside of the pack, which eliminates the need to squeeze it inside. Alternatively, I've been known to stuff the tent into the pack vertically, with the tent against my spine. That actually works pretty well.

There's a third option, which actually is the one I'd suggest for you: break the tent into its components and pack it that way. Most tents are made with a two-piece fly and canopy design. So just buy small stuff sacks for each and stick them into different parts of the pack. And this way if you have two people you can share the load. Keep in mind that the storage sack most makers include with their tent is really just a convenience item that allows them to pack everything together neatly. It isn't cast in stone that you use it. Myself, when I've tried to pack a lot into a small space I've tended to stuff tents very tightly into after-market stuff sacks. It doesn't harm the tent, and of course I re-pack them in breathable, loose storage sacks when the tent is at home.