It's true that other jets exist, especially regional jets, but remember that these serve overall a fairly small percentage of the seat-miles (aka miles flown * number of seats) overall since they are smaller and fly shorter routes.

In some ways this doesn't matter that much (since these planes might actually do many more takeoffs and landings per day/week/lifetime and have to be engineered for that), but in other ways it does matter a lot.

As for the other companies you name, I will admit I am not familiar with them. Is there something relevant to add to the discussion from those companies? I would be curious to learn more