Don't know if they are worth a try at $4000 but I have a pair of Shure SE846 IEM for $1500 and I have never heard anything even remotely as good in an IEM. These IEM sound very close to the very best open back cans I have heard and have incredible noise reduction because of the great seal with memory foam.
I heard the $4000 Focal Utopia Headphones yesterday
Very nice. Very expensive. Beryllium drivers. Reviews a bit hyped I think. Who would pay that premium otherwise? Not sure I could live just with any headphones still.