5 yr locked in rates - Why not for existing customers?

I'd like to know why xfinity rewards new accounts with 1G for $50/month locked in for 5 years, but a loyal customer of now 14 years - the best they can do is $70/month for that same plan locked in for only 12 months? I spent over an hour on the phone with customer service only to be told that there's nothing more they can do for me. As a Verizon customer (for my mobile phone) of over 20 years, they offer me monthly discounts all the time for being a loyal customer (not that they don't already cost too much to begin with, but anything helps in this insanely transactional world we live in). So what's up with guaranteeing newcomers 5 year rates, but not loyal customers? I moved 1 year ago, and rather than start a new account, we paid to transfer the account and still were only offered 1 year rate, even though we were the first to have xfinity in this rental (we had to have it installed from the pole outside), yet I was told new customers were offered 5 yr rates starting last July (we moved last September). If I close my account and take the new AT&T fiber offer for $50/mo for 1 year, at least I'd be saving $240/year with them. Or if I close my account, but my roommate starts a new account, then we could take advantage of the 5 yr rate?

MAKE IT MAKE SENSE.