You are wrong in your assumptions. I am very much up to date with package holiday costs and flight only seats.
During this booking process customers (along with those on flight only) will be given the option to pre-book extra space seats (very limited availability as they are on all airlines
Yes you are correct, but these are Emergency Exit seats only and
NOT BOOKABLE if you are elderly or frail, have any medical problem, disabled, obese or under 14 etc. It is not stated what qualifications the cabin crew will have in making a decision to refuse seating for most of these conditions.
Last year I took a Thomson Platinum holiday which was excellent in every respect. The holiday included free selection of standard seating. This year there is a charge of £15 per person for the same facility and £50 per person for Extra Legroom seats which of course is not an option at all if a cabin crew member can refuse seating on the basis of being elderly or frail without definition.
As I say, some low-cost airlines have genuine extra legroom seating that is available to any passenger at a supplement, not just flogging off the seats that just happen to be adjacent to an emergency exit.
The charter airlines are just as good as low-cost airlines in the choice of chargeable extra's but not as good as some when it comes to seating comfort and choice.