Yet I can't ever think of a Ryanair flight I've seen go out with a single spare seat. There are plenty enough people who don't mind abuse of the save a few cents. Good luck to them. Keeps them off my flights.
I think that for the average person, not represented on this website, it's actually very important to save money, and just suffer the cheapest option available.
I've taken maybe 16 ryanair flights this year (it's the only airline that does the city combination I want), and more than half of those flights have gone mostly empty. Those flights were also the cheapest. The ones that went full were the most expensive.
So feel free to add my anecdote to yours, and derive nothing statistically significant besides that I fly a route that is only intermittently popular.
..I'm also flexible on dates so I deliberately book cheaper days, which may make for self selection in this way.
16 flights this year already? I guess it really is dirt cheap to fly around Europe. For me, flying in Canada is expensive, and such an ordeal that it isn't something I could see myself doing that often.
The cheap trips clock in around 60 euros return. The expensive ones have clocked in around 100 euros return. Honestly, parking at the airport is more expensive than the cost of the flights most of the time.
I find that the best way to avoid abuse is to fly first class. Plus, it includes free checked bags, champagne, and a nice curtain to hide the view of the peasants.