The main issue are not the developers. In my experience its the pressure the company puts developers under. Most developers would love to take time develop well designed software. But most companies push, push, push for more features in x time. The first thing that gets cut is design discusion and the ability to go back and improve old code.

The older the developer, the harder they are to push around(They've seen it all before, probably been a manager before) and probably why we have a agist industry because companies like developers they are easy to manipulate.