Why no sequel?

This movie was a surprise hit and I remember at the time of its release and afterwards it had great word of mouth (no pun intended). It felt like a movie that came out of nowhere then seemingly everyone was talking about it. If I remember correctly there were plans for a sequel titled "Project XX" but for whatever reason it fell thru.

I think had a sequel with the original cast returning, it would have been a hit and assuming the sequel would have made a lot more money than the original, we would have gotten a third film.

Who knows after that! It might sound like a reach but I really thought Project X could have been sort of like that generation's American Pie. I do not understand Hollywood.

They make sequels to films that do no warrant them yet when an opportunity like this comes along where sequels would have been necessary, they don't do it. They really dropped the ball here. Who agrees?