By "Under one roof"- I hope you're talking about the Studio and not Leatherface and Jigsaw in the same movie.
I would suppose all of these remakes and team-ups are a outcome of "supply and demand".
Like I said the other day...it's suddenly dawned on me that the blame for all of these things are the average, youthful film audiences who really couldn't care less for the classic originals, are NOT "Horror Fans"and just want to see those "stupid, old school horror movies" REMADE with advanced technology.
We,Horror and Sci-Fi fans love those movies and are usually pissed-off every time one is remade for a bunch of "kids".
But,going to a movie will always be the "Date Event" of choice...so, the majority rules and WE can either be depressed or excited.
I, personally, wait for them to go to the "Dollar Theater" and that's ALL the money these fucking idiots get from me...if AT ALL!
Then I go home, pop-in the DVD of the "Old Classic" and feel a little sad for the kids that didn't want to watch it.