I know I purposefully do what Michael said so I get a reminder when something doesn't go through so I can re-evaluate if I want to continue paying the subscription.

I'm sure I'm not alone in this.

Also, you said "most" don't go through, which mean some are? If so, it's probably not your back-end setup. If you have a 0% conversion rate from trial to paid, I'd look into that ASAP.