Teaching seduction isn't something suited for a TV show. Every person has assets and hindrances of their own, and some have more assets and less hindrances than others. So, it'll take each guy a different amount of time to excel at this stuff. The kinds of people that actually fit for a show like this are those that would take the least amount of time.
Having said all that, I think Mystery realizes this, and then you add the fact that he has to ensure there will be good TV throughout the show. So, he'll naturally keep around the people that are doing the best, and that don't have a whole lot farther to go as well. He has to crown someone a "Master Pickup Artist" at the end, after all. Whoever this ends up being will have to be.... at least, like....... decently ok at pickup.
Anyway, about cutting Fred. I don't think he belonged on the show in the first place. Its not that older guys can't hack it, because they can. The show just seems to be intended for the 18-25 kind of audience. And no one over those ages watches the reality shows on VH1 anyway, lol. While I do believe he can improve himself a lot, and eventually get good at seduction, it'll take him much longer than the show allows. And he'll have less success as well, since he's a 45 year old going to bars 20-somethings frequent. The show just isn't right for him. He'd do much better on a personal journey, with advice like you can find here.