There is no orphan drama when there is a hard fork. Blocks on one chain are simply invalid on the other one, and respective miners build on one or the other.
you have been mis sold the fake dooms day speech by blockstreamers
I'm not even aware of what blockstreamers say. I just apply logic to the different possible outcomes.
My point is that nothing of all this will ever happen. Bitcoin will simply stay as it is. There will not be segwit, nor BU.
Unless:
1) bitcoin is further centralized, and that centralized entity decides whatever it wants to decide
2) bitcoin loses its first mover edge. At which point I think non-consensual hard forks will be possible.
But in as much as the consensus mechanism of immutability remains at work, there's no possibility for any of this.
I'm just exploring the logical possibilities of the different actions.
The biggest clusterfuck that can happen, is a backward compatible hard fork that loses miner majority after 6 months.