1) Home phone?
2) Because I hate Comcast. They constantly mess up my bill, charging me for extra cable boxes that I don't have, etc.
3) I have a $30 / month (comparable in price) cable package from Comcast (only because it was free for a year with internet bundle), but it's missing some key TV channels like ESPN that YouTube TV includes, not to mention the cable box is huge, slow, buggy, and doesn't have any DVR features. For better channels and a better cable box with DVR, I'm sure Comcast would charge $60-$100, which is then priced much higher than YouTube TV and not comparable.
4) From your own math, $50 for internet plus $35 for YouTube TV is a heck of a lot cheaper than the $120 you're paying. Seriously, lose the land line and free yourself from overpriced 3 in 1 bundles.
5) Did I mention Comcast is terrible? Seriously, I would rather give my money to any other company. Comcast is the worst company in America, and AT&T and Verizon aren't far behind.
When my free year of Comcast cable TV is up, I'm dropping to internet only (they are the only option I have) and might pick up some service like YouTube TV.