I do support this bill for a simple reason: You sign for service X for 2 years. After 6 months, the service is degraded for any reason, or the company decides to alter something that makes the service less valuable to you. It makes sense to have a clear picture, and a cap on costs, so I can decide the cost of 'betting' that this company will be able to offer consistency over the period of my contract.
I understand that the businesses like to know their future income to plan things ahead, but as a customer you have little protection in the quality of the service changes, and you don't feel like a battle with the mandatory arbitration company of their choice.
I generally support consumer protections, though California already protects against situations like you mention: if the service degrades, or the company makes an alteration, you have recourse to cancel. To add to your protection, put the recurring charge on a credit card and the CC company will go to bat for you.