Firstly, hands up, much as I am interested in aviation, I rarely fly but I book several flight a year for Mrs R and this seat reservation thing drives me nuts.
She mainly flies alone and on trips of less than 2 hours so objects to paying a premium for selecting a seat rather opting for the auto-allocation.
On some occasions she had been asked to move to the emergency exit seat because they are empty, when she would have paid 10/15 euros if she had selected them as a option.
Michael O'Leary said that these days an airplane is a bus with wings, and that just about sums it up on short haul. The thing is unlike a bus or train, you will always get a seat somewhe on a plane
(for the time being, at least!), but at the moment it's all a game and if everyone refused to play it the airlines would have to change their game.
My response is generic to the issue and I understand some people have specific needs around seating.