"Rutan won the X-Prize"
Yes, he did, but he did with an architecture incapable of doing anything more impressive than win the X-Prize.
I'll give you another example from the self-driving X-prize.
There were always two teams that were very close to winning. One team hand-coded every decision tree for the particular path the car might encounter, and the other team used machine learning and let the car figure it.
Now as it happened in the self-driving challenge, the machine-learning car won, but it was really, really close. For the limited purpose of the challenge, the hand-coded car was nearly good enough. Maybe if they'd hand-coded it just a little better, that car would have won.
But hand-coding doesn't scale from a closed challenge track to real-world self-driving cars. Only machine learning can do that. But because of the artificial constraints on the challenge, the non-scaling solution almost won.
Well for the Ansari X-Prize, the non-scaling solution DID win. That's the Rutan solution, which used wings, which work for 1 passenger but (as Branson has spent 20 years and a billion dollars proving) doesn't even scale to 10 passenger joy-rides, let alone orbit.