Of course there are - an unlimited metro card is $132. the person you're responding to is nuts - no one that commutes from Bronx to downtown is paying per swipe.
I assume an "unlimited metro card" also includes unlimited buses too?
A 2 zone is $220. I think in size that's roughly comparable?
And in my experience people who mostly take the tube rarely make use of buses. They'll walk or take the tube
Edit: well if you live in a part of the city that has good coverage - up in the Bronx it's not so great naturally so I wouldn't be surprised if those people didn't get as much value out of a monthly card.