Right. You aren't a NYT customer. Really, you aren't worth their bother.
And yet I am reading their content for free where I'd be willing to pay something. It seems sub-optimal. I figure that I read about 3 NYT articles a week, or 12 per month. I would happily pay $0.10 a read, and wouldn't mind ads. So, theoretically they could get $14.40 from me each year before ad revenue. Apparently Facebook's revenue per user is was $6.40 in 2013, and Twitter's was $2.76. Of course, it's apples to oranges, but at least the numbers are in the same neighborhood. With ad revenue, I might be worth $20 per year to NYT. It's far less than the $144 that b_b is paying, but it's significant.
I would have to think that they would have run the numbers and decided that it isn't viable. I suppose that one risk is that b_b would convert to a pay-per-read customer, and they wouldn't get four more customers like me to make up the difference. Also, credit card transaction costs are going to eat up a lot of that revenue, especially for customers that read less than I do. Finally, I would be less likely to subscribe to a NYT pay-per-article account than I would to a service that let me pay-per-article across a number of outlets.