A nice question.
If you look hard enough one will find a weakness even at the strongest looking move.
Only Checkmate is the move without weakness.
As in all other aspects of the game you have to weigh up the Pro's and Cons.
"Although c4 stops d5 and grabs space, it weakens the b2-g7 diagonal and you lose the right to support d4."
2 c4. does not stop d5 (the Grunfeld).
The weakness of the b2-g7 diagonal is debatable.
The g7 Bishop is eyeing the squares e5-d4 and c3. (central squares).
Very often you will see White give up the b2 pawn and even the a1 Rook
to get that g7 Bishop off the board.
The d4 pawn does not need support, it is already being protected and it
is quite a hard to attack d4 with natural developing moves because
as White it is quite hard to make natural developing moves without further protecting d4.
The biggest gripe I have v 2.c4 is the unmentioned fact that the f1 Bishop
does not get it's famous square c4 and the a2-g8 diagonal and a minor
moan at the weakening of the d3 square which has undone unalert White
players on many occassions.
However experience (the study of the Games History) has shown that
White has more chance of holding his opening plus if he does not block
the c2 pawn with a Knight after 1.d4.
White places his piece ready to take (hopefully) advantage of Black's
eventual stab at the centre. d5 will result in a flank pawn being swapped
for a centre pawn, so the usual breaks are going to come via e5 or c5.
Also Black has a better chance of challenging White's centre if he
does not block his c-pawn with a Knight - of course there are always
exceptions, nothing is set in concrete - The Chogorin defence 1.d4 d5 2.c4 Nc6.
[en]r1bqkbnr/ppp1pppp/2n5/3p4/2PP4/8/PP2PPPP/RNBQKBNR w KQkq - 0 3[/fen]
Black is shaping up for a quick e5 to resove the problem of the centre tactically.
So althoug after 2.c4...
"...white is committed to playing in certain type of way."
So does Black and by studying the games played by great chess players
and that is the only place we can look, we can see that the Pro's and Cons
Though personally if I was a 1.d4 player I'd always consider 2.Nf3 as it
stops the Budapest's and other gambit.
Of course that rules out the f4 attacks v the KID/Benoni and Pircs.
(pro's and con's.)
There is nothing wrong with 2.Nc3
Tartakower played it many times as did Richter, Alekhine popped it
out a couple as of course did Bent Larsen.
Johnny Hector often played/plays it.
Loads of people on here will try it after seeing this inspiring game.
(we need a Johnny Hector thread and the chess publishing world needs
Johnny Hector's Best Games
J.Hecotr - Kirkeggaard, Politiken Cup 2006.