The super expensive CB for now so far is Hifiman RE10 (Planar Version), not counting the cosmetic luxury item out there, like beats diamond headphone (if this considered then closed wil be super expensive instead of open back counterpart), and not discontinued item (if we talked about sony r10 that's different story), but it seems there's no one tried making flagship e-stats closed back one so far, probably it's not suitable for closed setting, also those hifiman seemed not popular among audiophiles, the open back counterpart is more popular, like he1000 or susvara.
If we talked about sealed, well, ppl usually/tend to use IEM instead of CB headphone because of it, even there's an iem more expensive than TOTL closed back, in iem open back is somehow rare, that's why perhaps the reason, i conclude there's not many TOTL CB that actually success compare OB counterpart, the expensive most popular one is fostex CB and it's mod/variant in audiophille community compare to others, i;m not talked about SQ and preference, just their popularity in community in general, you can start to audition them to know why ppl choose them instead of open back counterpart, probably because there's something special that cannot found in iem or even CB one, for the reason, probably that's why fostex OB seemed not popular as their CB for example.