Unhhh, maybe two, not ninety.
Believe me - I went through plenty of discussion about the number of B-2s back when the article was first published. Total cost of a B-2 (not just the aircraft itself) includes lots of add-on high tech equipment that is very expensive as well as operating and maintenance costs over its lifetime. Just getting a strip-down B-2 to park in your driveway is a lot less expensive than the numbers you’re thinking of. The numbers given in the article were not just off the top of my head.
I read once that the B-2 would cost less if it were made of solid gold.