I wonder if there's a name for this phenomenon. You can often guess at some things' decade of origin from the suffix. "o-tron" "o-matic" for instance were 40ies and 50ies.
And I don't think the phenomenon is a negative one. Just as clothing fashion changes so does naming fashion. For some reason we feel that names should have a timelessness to them, but clothing should not? Both exist to engage humans on an emotional level and human engagement will change over time due to exposure to the current trend.
IMHO Rebranding long lived companies > Stressing out about finding a 'timeless' brand. Optimizing your brand must take temporal concerns into account.