I don't think the quality of pilot has anything to do with their age. I also don't think that it has much to do with whether they learned to fly two years ago or twenty years ago. In my opinion, it's all down to the quality of the initial instruction they were given.
If you are taught well in the early days, you will learn good flying discipline and continue to use the right techniques throughout your PPL and beyond. If you are taught bady, perhaps by in inexperienced hours-building instructor, you will pick up bad habits, which will exacerbate with time unless they are stamped out.
The type of flying club also has a lot to do with how your skills mature as you gain more experience post-PPL. As others have already said, commercial flying schools ofter don't want to know students any more after they have passed their PPL, unless they are forking out more cash to pay for advanced training, such as night or IMC. This means that you are out on your own, and unable to benefit from the experience of other seasoned aviators around you. A proper members' club will always be a welcoming place that attracts high-hours private, commercial and ex-military pilots.
As for the cost of keeping current, a non-commercial club will tend to have cheaper flying rates, because it's not trying to cream off a profit. If you're paying more than £80 an hour for a Cessna 150 or PA28, you're probably in the wrong club.