[hellofunk]

Two points:

Blender is not a renderer, it's a modelling and animation program with a built-in renderer, Cycles. But it can connect to other renderers, too.

Cycles is not that old. It replaced Blender's prior renderer just a few years ago.

[object_destroy]

Appleseed has also been under active development for 7+ years; so not that young, especially considering that physically-based renders really only started coming into full production use 3-4 years ago. There are still many visual effects studios using approximation-based setups today, so I'd say there's lots of room for "new renderers" to carve their niche.

[redpanda_ua]

I know Blender is not a renderer, but they include 3 renderers in the package: Bledner Internal, Cycles and, Blender Game (This one is Real-Time though).