Queens gambit: what about b6?

When I have black, I like to answer Queen´s gambit like this:

White: d2 - d4  Black: d7 - d5

White: c2 - c4  Black: b7 - b6

This b6 gets a low rating in many chess books, but I don't understand why. For me it prevents White: c4 - c5, which will block black´s bishop. 

Any comments?

Because white now can just take the pawn and play cxd5, and black is going to waste his time by taking it back with whatever piece he use.

There's no need to prevent a bad move like an early c4-c5, you can play b6 after it just fine:

While not the best choice, at your level its perfectly playable.

White and Black now possess almost same weight. Good.

I'm at work, that's just a line i threw out there :-)

Its probably not the right way to view it, but i was thinking of what the OP would encounter the most.

Thanks for many good answers. I especially appreciate the comments from Haruuun_OO and IMBacon. However, I still think that white: c4 - c5 blocks the black bishop, which should be avoided, and so far as I can see b7 - b6 is still OK, but I admit that the disadvantages has been clearer. 

Thats just a fundamentally wrong way of thinking about it, even though yes, you can play it and it won’t lose by force. 

Thanks for the replies to all. I understand that b6 eventually may occur later, but that it is more important to develop in other ways. I still have a problem with the black bishop, but I accept that it is other things that should come first. 

Thanks to everyone who contributed! You are good people

You shouldn't worry about the bishop at all - it normally goes to e7. In fact, white playing c5 indirectly activates the bishop because it pressures the pawn, hence it's not something you should think about. Here's an example:

My preference would be 4.f3.  Now that's some center control.

Your c4-c5 will work now.  But if you're choosing to improve, and grow in chess?  It may be a habit you want to start learning to break now.  But whatever you decide I wish you luck.

Thank you everybody. I learned especially much of the two games which SharedUser and IMBacon shows. I think I have solved my little problem now. 

Obviously you cant go wrong with either move...It will come doesn to preference.