CNBC averages around 250k primetime viewers (under 200k during the day). Its top show attracts fewer than 400k. Imagine how much lower viewership would be if it wasn't a "free" channel. There's essentially no economic model that allows them to stay in business in an a-la-carte world. But if they are guaranteed to be in 80 or 100 million homes via bundling, then yes it can (and does) work.
According to wiki CNBC has the highest income audience of any cable station and made $300+mm on $600mm+ in revenue. I’d watch it but I don’t have cable, I bet they are missing a bunch of Ad revenue from people who cut the cord.
https://ctv.kwayisi.org/networks/cnbc/