I'm sure Brooks have figured out exactly why they should NOT produce a synthetic saddle,
Actually, Brooks has already manufactured a couple of synthetic saddles that have come into my possession - a mattress and a plastic covered one. Neither impressed me one bit. I should add that I have a hard plastic San Marco tucked away in The Old Shed and I will never use it. To me, plastic, even the infamous Dupont Delrin used in Simplex derailleur, has no place on any of my vintage road bicycles. But that is just me.