Earlier quoted context omitted.
Easy! :s/SOPA/PIPA/g PIPA, the sister bill coming through Senate, is still there and needs to be squashed as well.
Once it's been canceled in either branch it's dead. They both need to pass it for it to become law so PIPA doesn't matter anymore except maybe symbolically.
I don't see why you couldn't have a situation where PIPA supporters lay low for a news cycle or two, then get PIPA approved and sent to the House when nobody is watching. PIPA is even more generically-worded than SOPA, so it will be more difficult to fight it on the basis that "it will break the internet".
There is clearly a lot of money riding on this bill, and it's election year.