So we have a few options here
1) The ending is as plainly the way it looked. Shep meets magical space child, you choose different colored explosions, for some reason the crew that was with you on earth landed in some jungle.
So, Bioware wrote a really shitty ending, possibly rushed for time.
2) Indoctrination theory where nothing that happened after being hit by Harbinger's laser really happened. It was Shepard's mind fighting off indoctrination. His/her conversation with the Illusive Man was representative of his/her own struggle to keep a grip over their own mind. The choice determined whether you wake up or not and did not actually cause pointless stone age-ing of the galaxy. For whatever reason, Shepard is shown an image of your crew crash-landing in a jungle.
So, Bioware did not write the ending of the game to either leave it vague or to sell you an ending later.
3) They ending was just a feint while they were rushed for time to make an actual ending. It will come out eventually.
So, Bioware sold you an incomplete product, but intends to fix it eventually and was not out to PURPOSELY screw you out of an appropriate ending.
It's kind of funny that the best possible choice for Bioware - as in, the option above that makes them look the least incompetent and sleazy - is the one where they tried to write a clever ending and just threw up all over themselves.