What you played 30 years ago may have all burnt to a crisp by now, and in any case, appeals mostly to an audience that is three decades older than today's target. The 25-54 crowd of 30 years ago is now 55 to 84.
Yes, among people in their 60's and 70's. Stations don't stay true to their music; they stay true to the target age group.
One, research is a snapshot. A picture of people's tastes at a given moment for a particular age group. 30 years later, we don't care what that age group wants to hear. They may or may not still like those 50's and 60's songs, but we are not gonna' play 'em because we can't sell a dime's worth of advertising if our average listener age is way over 55.
Specialty shows are an excuse to play off the playlist, but once and only once on a holiday weekend when radio listening plummets in PPM markets. It's novelty value, and we know that such songs played regularly will do nothing but create tune-out.