The cost to do security checks on people scales with the number of people. There are plenty of taxes and fees already included with plane tickets; whatever "security fee" is actually necessary to fund reasonable security can be tacked onto the cost of tickets that way, and will automatically charge more from people flying more often (and won't penalize people who don't fly at all).
The only possible economic benefits separating it out into an optional multi-year subscription service provides for any party are 1) overcharging people who misgauge actually "needing" it when they don't end up flying enough to meet whatever your threshold for judging that is, and 2) actually not fully charging super-frequent fliers for the amount of workload they put on the system.
But who is going to keep up with the “frequent travelers”?
The fee is tiny compared to the costs of a plane ticket. It's $100 for multiple years of validity.