Sure, without getting into ageism or anything divisive or rude. Most of the older pilots in that range have been out of the industry or never in the industry and have been flying small planes around for years with little to no flight instruction given or dual pilot situations.

Additionally, it's no surprise that as we get older it becomes more difficult to learn and/or adapt to new training as people get stuck in their ways and are less sharp as they age.

This is not true with everyone and much of success in training (both ground, sim and IOE) depends on someone's effort put forward. This is true with any age group. Young and older.

United, Delta and American target most people in the early to mid thirties to early 40's with turbine PIC time. If you have a problem with that you should ask their HR department about it. Will leave it at that.