How are fare classes priced - difference is more than the value of the perks?

Not just specific to WJ but always wondered why the flex and non-flex fares seem to differ by more than the value of the benefits.

For example, I'm looking at YYZ-ICN where EconoFlex is $2,700 and Econo is $1,700. AFAIK you basically get to pick seats and refund your ticket with flex. The cancellation fee for an international fare is $150. Idk how much it costs to pick seats on this flight but there's no way it makes up for the other $850.

Same thing with Air Canada. I understand at the Latitude level it could be upgraded to Business so you're kinda paying for that, but the rest...it makes no sense?