Why are all quasars so far away? Why are all quasars so far away?

If the universe is homogeneous, we could expect to have a homogeneous distribution of quasars, but all of then seem to be far away from Earth. Why is that?
There are essentially two reasons.

First, quasars are rare objects, so even though they are homogenously distributed on large scales, the average distance is large. Moreover, the brightest quasars are even rarer, but visible to large distances, so their average distance is even larger.

Second, most quasars were most active at redshift $z\sim2$. This is thought to be because quasar activity is triggered by galaxy mergers, which bring gas into galactic centres so that the supermassive black holes can be fed. Galaxy mergers and star formation peaked at $z\sim2$.

Finally, there is some bias in the sense that astronomers are looking for the most distant (and hence oldest) of objects, because they are more interesting than nearby objects when it comes to learn about the formation history of the universe.