Have you considered charging 20%? Think of the value you'd be forced to provide! :)
In all seriousness, this is a good attitude to have, except that switching from you guys to someone else is going to be genuinely painful. The provider I use now has an API and provides full CSV and JSON exports of everything, and then all the actual payments live in Stripe. Switching should be a snap, right?
But it's still a pain to migrate over the user accounts, force users to reset their logins, setup new subscriptions with the same different billing amounts (prices have changed over time), discount codes, and billing dates, ensure that everything continues smoothly so I keep getting my money, switch over all the integration points with my site and analytics, etc, etc, etc.
It's such a pain to switch that many just won't bother to pay that big upfront cost in order to save money every month going forward and will just put it off, which is why I find this pricing model to be particularly aggravating. They wouldn't have signed up for it in the first place had they known, but they didn't know and now they're "trapped".
I hope you're just underestimating the difficult of switching away and not counting on it!