@Molecular wonder are you an American resident/citizen? If so, I think this could be a factor they are taking into account.
I don't think age should be a factor as long as you have things that make you stand out. As @LoveMysterious mentioned, coming from industry and mentioning that you want to go back to industry after getting your PhD might be a "kiss of death". Depending on the program you apply to, some faculty might feel like you might not need a PhD if you want to stay in industry (in fact, some of them might think a Master's could be more appropriate) and that could be affecting your applications. I hope you hear back from the other schools you have left to hear back from tho! I know it is hard sometimes to avoid feeling "bitter about society", and I hope we (the grad school cafe community) can help you with that.