Brian_227 :
Why would they release D1 now? They're going to release the sequel on PC in a month, nobody is going to want the first one.
Possibly because there are thousands of people on PC who have never played destiny 1 and probably want to get the first game out of the way before they buy the second? Its almost like its a simple concept.
Additionally, some people cant afford a 60 dollar launch title plus DLC, but would still like to play it once it gets cheaper (as in years after launch)