[Retric]

The best older developers are often really interested in new things. The real separation is more Hubris vs. Expertise. An expert knows how to get something done so they may take risks with a fall back option. Younger developers often have no fall back option other than just blowing deadlines or working at 2AM.

In the end the real 'problem' with older developers is they expose problems with your organization by providing what you ask for. If you keep asking for tight deadlines thinking people are going to ignore them you squeeze out creativity.