Only 2.4 million out of 91 million was raised by kickstarter. The rest was traditional venture capital from places outside of crowdsourcing. (The venture capital was raised after the kickstarter though.)
If the kickstarter was a stock instead of a promise of a product, then though 2.4 million stocks would be heavily diluted when the company issued another 88.6 million stocks.
---------------------
I also do not see what the big fear of everyone is about facebook buying Oculus VR. You only spend this type of capital when one of two things happen.
1) The company you are buying has some unique intellectual property or trade knowledge.
2) The company has a unique business model that will generate a return on investment.
Oculus Rift is nothing really unique with intellectual property all they have is a lot of trade knowledge, something that given enough time Facebook could generate themselves at a far lesser cost. Thus the only reason to buy OCR is due to time issues such as time to market, or they believe OCR has something unique about them that a different company (such as sony) does not.
2 Billion is a lot of money, if they sell 80 million units (the amount of xbox 360 sold after 8 years), they would need to make at least $25 dollars profit per each unit sold or they would not make money on the investment. That assumes there is no further cost to bringing the product to market (which is unlikely.)