What happened to DLC maps exactly? I'm lost..

I used to play a fair amount of DLC maps on Reach, like getting Anchor 9 and Tempest every few matches, playing FFA on Solitary and Condemned, and playing BTB on Breakpoint, Highlands etc. Did the players that have DLC just get bored of Reach or what? I really miss playing on those maps.

Most people don’t own the maps. If you were encountering them before, then it probably was due to luck. :\

As for BTB, there was a glitch where it was accidentally made DLC-required. Perhaps you were playing it during that time?