Maybe because most people see the VCD as a dead format. With the rise of codecs like DivX and the interest of people to play those downloaded movies somehow on their standalone DVD player, VCD and SVCD made a great return. I remember....four years ago, when I showed people my VCD and SVCD collection - around 500 anime (S)VCDs

- they didn't even know that such a format existed...they heard something about "Laserdiscs", but never knew what it was. Now suddenly, everybody knows what a VCD is and how to burn them (at least this is how it was in Europe over here)...but still, most companies - maybe Apple too - tend to see the VCD as a "toy"...
oh, back to the topic, why do you have problem playing VCDs under OS X.1? Works fine for me! Just fire up the player, choose "open in new player" and point it to the .dat-file....it works for me