Spiderman 3, etc.

I finally watched Spiderman 3 last night. It sucked, but not nearly as much as Spiderman 2.

I'm getting sick of moviemakers making a brilliant movie, then following it up with 2 crappy movies to fill out a trilogy. People go see these movies on the merit of how good the first one was, and by the time they realize how lousy the second movie is, their money is already spent.

What ever happened to the days of the good trilogies, like Star Wars (the originals) or Back to the Future?

It seems to me all the big movies coming out are the lousy end of a trilogy, or a 'twenty years later' revival of an old movie or character (Rocky Balboa, Rambo, Indiana Jones, Die Hard 4...)

Can we get a good original story combined with good moviemaking please? Is it too much to ask of an industry which moves money by the millions?