It's a very reasonable theory, and to that I would only add that fans also have a tough time letting go of the ghosts.
One of the reasons (beyond their all-time standard of play) Bird, Magic, and Jordan stood out so very much was that they came along at a very unique time in the history of sports media. On the one hand, the three major networks were still grabbing the lion's share of TV viewers; on the other hand, they were centerpieces of a new type of marketing. David Stern, very early in his career as commissioner, decided that the best way to sell his then-struggling league (recall the drug problems and tape-delayed NBA Finals of the late 70's - early 80's) was to showcase the individual stars of the league. It worked spectacularly well, and there were two additional factors which made Bird, Magic, and Jordan appear to be even greater than they were:
1) Bird and Magic played on stacked teams which seemed to play annually for the league championship
2) Jordan not only produced on the floor at an astounding volume, he also achieved it with an unparallelled artisitic flair
All of those cir stances would fall by the wayside over time. The three major networks lost substantial chunks of their audience, other sporting leagues and organizations followed the NBA's marketing model (thus reducing the uniqueness of the NBA's approach), and superstars who followed in the footsteps of Bird, Magic and Jordan, while brilliant in their own right, weren't quite as good as their predecessors. Even more unfortunate for the new stars, the league trended toward defense in the mid 90's (thus producing a lower-scoring, less aesthetic brand of ball) and the great rookies after Jordan weren't joining teams with Dave Cowens, Pete Maravich, Tiny Archibald, Kareem Abdul-Jabbar, Jamaal Wilkes, Norm Nixon, etc.
So when writers pine for the return of Bird, Magic, and Jordan, what they're really asking for is a confluence of cir stances that will very likely never take place again. Just like the rookie class of 1960 producing three Hall of Fame guards - the stars don't line up like that very often.