The one thing where I agree with cable companies about is the risk to consumers accidentally canceling all or multiple services when they intend to just cancel one. It will be hard to explain that a package price will no longer apply if one part of the package is canceled.
However- it can be addressed with a well-designed cancelation instruction screen. This is a constraint to the communication and process design; it is not an insurmountable barrier like the cable companies are suggesting.
As a software developer who only has business customers, let me tell you the following:
No matter how foolproof your system might seem. It never truly is. There is always some idiot (sometimes with a degree) who just can't understand/use it.
But they could still try and mostly succeed. They just don't want to.
You can't make a perfect UI, because people think differently. What is obvious and logical to one person, is obscure and nonsensical to another. It is impossible to make a one-size-fits-all interface to anything, not just software.
You could make a big, red, flashing button that says "pressing this button will cancel all your channels, are you sure you want to do that?", and you would still get an significant amount of users complaining that pressing the button did exactly what it said it would because users don't read.
The system now is that you have to call them, get bombarded with ads and berated by their customer service for an hour, then maybe they'll think about cancelling you. And gyms are even worse.
The system doesn't have to be perfect, just good enough to prevent most customers from accidentally cancelling more than they mean to. Anyone who fucks up can be handled by the customer service department.
I have a feeling they'll make it difficult to use. Then when people do it accidentally because of they're shitty UI, they'll point to that and say, "see?!"
No one will ever be in danger of accidently cancelling everything. The system will be intentionally designed so that you can only cancel one thing at a time, and that will be obtuse as possible. There will be a great risk of thinking you've cancelled something when it hasn't been cancelled, which will only be resolved by calling customer service.
You'll go through six to eight pages to cancel each item, and when you've done that you'll get a confirmation email that will require you to click on something, log in, and confirm the changes for them to actually apply to your account. If you get the confirmation email and do nothing, your changes will not save.
There will be a slew of angry customers calling customer service, who's job it will be to give back as little money as possible and retain every customer that calls. That job will be so awful that someone working that job will commit suicide because of it. The cable company will see that and market it as a success to their shareholders, and as an "easy cancel anytime" in advertising.