Those of us who make long distance journeys to London several time a month at eye-wateringly high anytime fares per journey (rates per mile much higher than for LTV▸ (London [and] Thames Valley)) along with plenty of others who do the same (the train is full before Reading and yet we are after the time that would get most people to regular work on time) will feel that we are the ones contributing the most.
I wouldn't want to hazard a guess which ticket type brings in more income..but I do know that if your journey is disrupted you can get compensation for your ticket. It has to be really really really bad for season tickets holders to obtain that benefit (and you'll be lucky to actually be able to claim it for a void day!)