We will soon find out with Southwest. They are moving to assigned seats because they think many travelers are avoiding them due to their open seating. However they may find that their most loyal customers no longer have a good reason to choose Southwest. Time will tell.
I’d like to see some airline adopt a seat + weight pricing. You pay a base fee and then you’re weighed with your luggage.
So what’s left to differentiate them? That they don’t serve food other than pretzels? That’s a big selling point?