I suppose that's the main reason as Houdini's real customers are those who can afford huge render farms. Even before Karma, Houdini's renderer (Mantra) wasn't known for its speed.

That's quite a bummer for me, an indie user. With the foundation Houdini has established, they probably could've released a real time viewport composition before Blender. But at the end of the day it doesn't make a lot of business sense for SideFX to care about users like me.