Fortunately for perfumery, ambergris' distinctive odor is principally owed to just two chemicals, ambroxan and ambrinol, both of which are now synthesized.
Probably a bit like synthesized truffle oil, good enough for most people but lacking richness for a trained delicate palate.
There's a curious evolution about abroxan's rep. If I'm not mistaken it was Dior that first used the name instead of ambergris in the publicity materials. I guess they were trying to avoid the "they kill the poor whales to make fucking perfumes". But they ended with the "I can't stand that synthetic ambroxan crap, I must be allergic and everybody's wearing Sauvage now".
New perfumes use some other bullshit names like "driftwood", "marine notes" or just "amber" (a very different stuff).