There are a number of possible answers to this question, here my 2-cents:

\begin{enumerate} 
\item \textbf{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.   
\item \textbf{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''.  
\item For some unknown reason, \textbf{the Universe is not gonna last as long as we think}. This is a sort of cosmological equivalent of the \href{https://en.wikipedia.org/wiki/Doomsday_argument}{Doomsday argument}. 
\end{enumerate}