(Then there's the factor of how much time and space all that also wastes at security checkpoints.)
Checked baggage has the efficiencies of forklifts and trucks and conveyor belts. Just as airlines fixed most of the problems with those systems and got them to be efficient beasts they decided to disincentivize actually using them by charging extra for what is the cheaper cargo space. I wish an airline would have the courage to reverse the fees structure and charge for overhead bin space instead. (But then I also travel with IBS issues and my patience in deplaning has been severely tested enough that I know not everyone shares quite my annoyance at deplaning issues in particular.)
And for the pedantic really small planes like Sansa in Costs Rica for their 30 minute flights between San Jose and other cities.
https://en.m.wikipedia.org/wiki/Quepos_La_Managua_Airport#/m...
https://www.vacationscostarica.com/_next/image/?url=https%3A...
But that has more to do with the realities of the plane and the airport infrastructure like you said. It’s not about airline policy with regards to checked bags vs non checked bags.
On that plane, they not only weigh your bags, they weigh the passenger to make sure the plane isn’t over the weight limit.