As a society, we are absolutely CRUSHING the use of "crushing it." Not just that, we're killing it. Actually, really we're KILLING the expression "crushing it," and we're CRUSHING the expression "killing it."
That's what we're doing.
We are crushing "killing it" so hard, that "killing it" has been reduced to tiny, subatomic shards of neutrinos. Those eensy, weensy little microscopic bits of matter that Neil deGrasse Tyson calls "star stuff." That's how hard we as a society have now crushed the phrase "killing it."
We have also KILLED "crushing it," to the point where we as a collective populace have committed an unclassified linguistic felony, and the expression has undergone rigor mortis. It's a cold, blue, dead corpse, lying on a freezing slab of slate in the city morgue under a sheet, with a tag on it, just like CSI Miami.
Yep. It's official. The expression "killing it" has been totally crushed, and the expression "crushing it" is dead as a doornail.