No, not at all. It isn't really about age. I've dealt with "hipsters" in their 40s and 50s who've come up with very bad UI designs. Likewise, many of the managers or executives advocating for these redesigns are in their 30s, 40s or even 50s.
While it may be more of an issue with younger people due to a greater lack of experience and intuition, it's a phenomenon that's quite independent of age.
It's usually about a class of people who have helped to design the systems we have at present and who are therefore heavily invested in those systems in a variety of ways reacting negatively to a class of people attempting to help design new systems that they will one day defend due to their investment in them.
The idea that UX was better in the 1980s kind of gives you away here.
Are you really suggesting that people can't have second or even third careers?
A 40-year-old who got into web design after a lengthy career in print media design, if not some totally unrelated field, is often no more experienced than a 20-year-old who got directly into web design. I know this can be true, because I've worked with both types of people in the past.
While it may be more of an issue with younger people due to a greater lack of experience and intuition, it's a phenomenon that's quite independent of age.