Developing pawns is almost always the same as creating a weakness, and here the d4 square is severely weakened. Much better would be to develop a piece, or at least make a different pawn move that doesn't make a huge weakness.
1.e4 2.c5 3.c4... Why not?

This is playable, or at least some believe so:
http://www.chess.com/opening/eco/B20_Sicilian_Defense_Staunton_Cochrane_Variation
it also hems in the white square bishop and doesn't let out any piece that wasn't already free to leave.
Can't you just play nf3 to protect the d4.. I know it's not good, but what makes its SO bad.. It literally loses 75% of the time while not doing anything dubious or ridiculous.
c4 is fine, i feel that in order to capitalize on any sort of weakness here black has to create weaknesses of his own for example ...2 Nc6 3 Nf3 and black is forced to play 3... e5 in order to stop 4 d4 from white, which would leave him in what i feel is a very pleasant position which is very open and leaves black scrambling a few moves behind to establish some sort of central control. but after e5, white can use his one move advantadge and play moves like d3, nc3 - d5, ideas of a4 -a5 and b4 at some point seem apropriate, and an eventual fiachetto of the light square bishop. White's chances are good, and his one move advantadge is put to full effect. Its a matter of preference really, but i think it is strong if played correctly.
1.e4...c5 2.c4 I mean.
I've looked at this opening and I don't see anything really wrong with it yet it's never played and those who play it apparently lose almost always on white.
What's so bad about this opening? It develops 2 pawns into the centre of the board.