There is no defense for a $6K OTR suit. Well, there is no defense for paying $6K for said suit.
UNLESS....everything is just perfect and you feel that for the same $'s spent on bespoke you could not get a better fit and fabric. Personally, I think you could spend 2/3rds of that and do better by going bespoke.
The other perspective is if you are a complete brand whore and have to have the world know you spent $6K on a Brioni at NM, then do it.