You must be comparing prices from different years and different seasons. For an accurate comparison, you have to compare current prices in the same season.
For 2012, the lowest price for a garden view room at the GF is $460/night. The biggest discount I have seen
on WDW rooms is the Buy 4 Get 3 Free deal, which by the way, they haven't had for at least 2 years now. Staying 7 nights and using that discount would be equivalent to a 43% discount (rounding for simplicity sake). Apply that discount to the room rate and you are getting a rate of $262.86/night. The more recent discounts are closer to 30% off but I think some people have still gotten 40% off discount codes.
The lowest price room at CSR during value season is $164. Even if you got no discount on the CSR room, you'd still be paying $98.86 more per night to stay at the GF.
The lowest price room at All Stars during value season is $84/night for 2012. That's a difference of $178.86/night if you have the largest discount on the GF and no discount on the All Stars room. That's 3 waterpark tickets right there.
And generally, there are discounts available at all resort levels, just not the same percentage off. So you'd most likely be paying more to stay at the GF than the numbers I've given above. Even upgrading from All Stars to CSR is going to cost you an extra $80/night assuming no discounts on either room. That's more than the cost of a waterpark ticket in just one night.