Because Bungievision would not use dedicated servers.

i am here on both sides of this story, the McDonalds wifi (crap wifi) side, and the no-lag side too. McDonalds wifi - we people over here gain very little power over our own lag, i for a fact was in the crucible with my friend once, and was shooting at him, but no damage, and he ended up killing me. other times too, i can go to kill someone, and since the lag doesnt register right away, theyll kill me first, and then die 5 seconds afterwords… literally. the only good thing about it would have to be making people like u mad because u think its the lag hurting u, while it actually hurts us. No-Lag wifi - over here, we strive on fast paced connectivity. i know when i see someone lagging i might have problems killing them, like shooting at them just to find there body lagging through space, waisting more bullets then normal to kill a lagger. there is only a small occasion where someone might lag just right and kill you, but i call lag switcher hacks on that crap ;) so trust me when i say, people with bad wifi arent any better, if anything we do deserve a couple of crummy kills for not being able to kill you right as we see you.