Exactly, after 15 years of web development, I never lock any customers into any proprietary anything. The cost, time, suffering, that come with the failure of a company we rely on is no longer worth it.
We have dealt with this a couple times with shopping cart providers, mls idx search systems, do-it-yourself website systems, captcha systems, cms systems (paid-for, now with no upgrade path for things like PHP5 to 7), payment processing systems, and more I probably can't think of at the moment.
If it's not open source, and self-hosted, then we walk away.
The only things we kind-of lock into now are hosting providers, email providers, and domain registrars. But we use pretty big and established operations for these just so we hopefully don't have to move things.