Shelf life is probably not an issue, at least if kept from getting dinged up and out of the direct sunlight.

The one issue is likely a slow evolution in design. Metal lugged to carbon lugged to monocoque.

The OP asked about failures in 10 to 15 year old "Name Brand" CF frames. If a failure mode had been identified by a reputable company, then it would have been fixed long ago... in the newer released frames.

So, the 10+ year old frame wouldn't have all the latest improvements.