Why do all the Ette seasons end with a proposal? More than a third of the Bachelor seasons don’t!

I was thinking that the Bachelorette’s F2 are probably put under a lot of pressure to propose. In contrast, we’ve had many Bachelor seasons - 11 out of 27; 40% - that had no proposal: Alex, Bob, Jesse, Charlie, Travis, Lorenzo, Brad 1.0, Juan Pablo, Colton, Matt and Clayton. Why the discrepancy?

Jen is the only Bachelorette who didn’t get engaged, but that’s because she rejected the proposal. Also I think about many Bachelorettes who probably weren’t ready to get engaged, like Gabby, Rachel, Tayshia, Katie, Jillian, DeAnna, and perhaps even Michelle. Why haven’t they been able to say let’s just leave as bf/gf? Thoughts?

Would Tayshia have ended up with Brendan if the proposal wasn’t emphasized? Rachel with Peter?