There are a number of possible answers to this question, here my 2-cents:
Due to a statistical fluke we arrived very early to the cosmic-life gathering. We can only sit here and watch the stars, mostly alone, and imagine what an amazing party it will be. Bummer. Stars less massive than the Sun provide a hostile environment for Life on a planet. They tend to be more “active”, which could prevent long-lasting planetary atmospheres. Sun-like stars might then be the best compromise for Life, and that’s why “here” and “now”.
For some unknown reason, the Universe is not gonna last as long as we think. This is a sort of cosmological equivalent of the Doomsday argument.