Because Burn decks which was the sole mechanic to the Volcanics fell through. It was easy to counter burn decks between '09-'11.
As for Macro, despite the name, Macro Cosmos isn't the center card. Dimensional Fissure and Banisher of Radiance are used a lot in both decks. Depending on the build you use, Control or Aggro, you set the decks up differently. Control Macro focuses on the monsters, a lot of lower powered monsters that are used to swarm the field and stay there as you slowly pull out the larger combos with the two Dark Monarchs or Zaborg/Mobius. Aggro focus on sheer power and prevent the opponent from summoning anything or pulling off summon comboes as the graveyard is blocked and everything is constantly removed. The Aggros rely on a lot of spells and traps to obliterate the opponent's field.
I'm a defensive type of player so my play style is slower than almost everyone and I just can't get into fast decks, so I tend to take my time with the beat down. I use the defensive control deck and combo DF/MC/BR with Gravekeeper's Servant to push an attack lock on my opponent.
My deck is like 4 years out of date as it can't use Synchros or Exeeds so I have a lot of work to do with it XD Which is why right now I'm running Twilight Dragons. (Light Sworn Engine)