I think you're bang on, except that VOIP is even more niche than secure email. Ultimately I think the problem is that email is effectively a commodity - domain

I think you're bang on, except that VOIP is even more niche than secure email. Ultimately I think the problem is that email is effectively a commodity - domain providers, hosting providers... well they pretty much give it to you for free. Google and MSFT seem to be competing on a value proposition like the full suite of office needs, even if it's for your person. I may be wrong, but I don't think that the average facebook using, instagram reading person even cares about email.