FWIW, I remember when Mozilla started experimenting with AI, and that was way ahead of the curve (around 2015, iirc?)
But yeah, I agree that buying a great email provider would be a very interesting step. And perhaps partnering with Matrix.
They need to give Thunderbird more resources first.
On the Matrix side we would love for Mozilla (or MZLA) to become a paid Matrix hosting provider. Element has ended up focusing on digitally-sovereign govtech (https://element.io/en/sectors) in order to prevail, and it's left a hole in the market.