One of the philosophies at Netflix was that it should be as easy to cancel as it is to sign up, because you should respect your customers enough not to annoy them into keeping your service. Honestly, it always seemed to me that it was actually easier to cancel than the sign up.
Any company that generates value for a customer doesn't have retention issues. I used to run software engineering at two subscription commerce companies. One company allowed users to cancel and pause/skip online via webpage, chat, email and even social channels. The other forced customers to call up support to cancel. The first company sold for 10 figures, the other company just did a down round and layoffs. Screwing…
And then there are services where people sign up but only a very small percentage would voluntarily come back no matter how good or bad your service is because they sign up out of impulse. Gyms are good examples for those — people sign up because they want to lose weight/stay fitter, etc but only a small percentage actually goes there after the first few times. This of course sucks for the regular customers who want to pause their membership because they are too busy for a few months or move, etc (but on the other hand, those no-goes also subsidies the regular goers because the gym can offer a lower price for everyone).
For those companies, we need laws that make it equally as easy to cancel as to sign up.