Two things - you're not paying for apps in any way, they're FLOSS. You're paying for services - infrastructure, administration, "cloud" space etc.

Also, while Purism is indeed a for-profit company, it's actually an interesting case since it's a Social Purpose Corporation - it's not there to maximize profits, but to maximize its social purpose. It legally can't do anything that would be at odds with its legally defined social purpose: https://puri.sm/about/social-purpose/