Separate antennas, yes, but only one pipe out of your house. Maybe you would be ok with sharing your line with other people, but most people are not. All those who don't have their own routers were not told it was happening. Whether it is "good" or "bad" long term, remains to be seen, but it's yet another issue where Comcast made a customer service misstep. If I had a Comcast router (and was still a customer), I'd be pretty bugged, and not only concerned about security but also concerned about some random people using up my connection bandwidth.

You may also be ok with yo-yo pricing, and perhaps you just love talking to customer service once a year to beg for your rates to go down again. Most people I talk to DON'T like that.