Oh wow, you bought it -- hook, line and sinker.
Of course it's built in!! You think they can just pony up ~$450 for EVERYONE who gets a new handset? No way! The reason your phone bill is so much is because they've built the subsidized cost into their pricing scheme.
That's why I always tell people like my parents: "Even if you're not going to use a new phone, you should go get one and re-sell it because ultimately, you're paying for the subsidy whether you get a new device or not."
Is my bill that much? I pay about $98 a month after taxes for unlimited data, text, and enough voice for my needs. That is pretty much on par for all the major carriers. I constantly travel around the United States so I need good national coverage. I understand some of the cost is built in but less the $100 a month is not particularly expensive for a single line with the unlimited options.