What do you mean a “single point of failure?”. It’s just becoming an office suite, same as Microsoft or Google. Thats a good thing, it means there will be a user friendly and intuitive privacy respecting alternative to the big tech alternatives.

The only thing I would reasonably worry about is scope creep that comes with managing too many apps at once, but the fact that Proton is just acquiring these tertiary services seems like their strategy for avoiding that problem.

As long as their primary product, the email, remains a focus I’m all for it.