Rabbit hole! Rabbit hole! Alert!! ....
INDEED!
So yes, the CFS engine is long, long past its prime, but as long as it still runs I'd rather OBD, as a small team, concentrated on giving us what they've been giving us for the past two decades, i.e. well thought out, quality releases of and updates to the world's most immersive WW1 combat flight sim, ever.
And anyway, consider how much CFS has been already enhanced in OBD's hands with the AI, self lighting and shadowing, scenery, maps etc. - already a huge quality uplift for trading back to MS for the source code, IMHO.