We learned our own answer to the Fermi Paradox in our first starfaring century.  Star travel was expensive.  The fuel alone for a single journey could bankrupt small nations, and finding the fuel in the first place proved challenging.  It stretched our resources to the breaking point to plant 80 colonies within 80 lightyears of Terra.  Then the Peloran traveled thousands of lightyears to Contact us and showed us that were much cheaper ways to see the stars.