As someone who spent quite some time (>1000hr) in Houdini, I really wonder what's the secret behind Blender's rendering engines and why SideFX failed to catch up. Cycles are so much faster than Karma on my machine. Eevee can get impressive results in real time while Houdini's real time viewport is bare bone.
The question is why don’t they integrate cycles? I mean I have a random app for home planning on macOS and even that comes with Cycles as the rendering engine. Can’t be that hard.
The thing is, Cycles is fully open sourced... so there is no real secret behind it!
Cycles is getting direct code contributions from all major hardware vendors.
Interesting, maybe major customers are insisting on other features ?
They've been investing heavily into this over the last 2 releases, but it's just that SideFX is a really small company. I think they have 50 people or so right now. Karma is way more accurate than Cycles, but slow. Karma XPU is a mixed bag.