I have to say it is frustrating how many classic Christmas specials have been phased out over the years, and barely replaced with good ones.
Which is a joke, if you ask me. Christmas specials seem like a corporate cash grab half the time, and none of the ones I've seen in recent years were memorable (Elmo included. And not even because of him, either). If Charlie Brown, rudolf, and Frosty weren't staples (Frosty is actually a generic winter song to begin with, as Christmas is never mentioned in the true, original song), they wouldn't even bother with them.
I don;t think it's just to satiate a ultrasecular fringe either. I feel that a lot of network ex tend to theink their own programming is more valuable ratings wise than airing specials. And half the time, the specials are really just lousy films that have Christmas in them (like Elf). And of course, since the majority of Christmas specials are available on DVD anyway now, networks tend to think that everyone can buy up every single DVD in existance (which is why they wanted to do away with reruns).