There's two sides to that.... first, these channels are included in a larger deal, where the more popular channels "carry" the impopular niche channels along. That way the channels get the same exposure as their more popular brother channels.
Second, if a channel is profitable, it doesn't matter how many viewers there are. If you can make a "watch paint dry" show for $3,000, and have the 1 hour show repeat 24/7 for a cost of $10k a month, and you sell $9k a month in advertising, (which is incredibly, stupendously low, but a a few paint manufacturers might bite) plus $5k a month from carriers who are forced to pay the $0.01 this channel sells for as part of a greater package.... the company will walk away with $1,000 a month. Put $500 back in the channel, so that after 1 year you can produce a NEW "watch paint dry" show with a different color, and you still add $500 to the kitty.
These channels are mostly being leveraged by their bigger brothers. And I have tuned in to obscure, never-watched channels before because something caught my attention, and that is what channels are hoping for.
When can I start receiving the "watch paint dry" channel. I would even purchase a 3D TV to watch it if it was available in 3D. If not then in 1080p HD would be my second choice. My third choice would be 1080i HD. Nothing less for me!