I have wondered this exact same thing myself, having discovered LessWrong in 2018 and Nate’s story very soon thereafter. We have a similar-enough background, though I’m missing the basic analysis course in university.
Your analysis lines up with almost everything I have gleaned over the last year, when things have seemed much quieter.
My effective conclusion—in absence of more information—is that MIRI is “full” like one is full from a meal. It would be nice to have more people on the mathematical side of things, but it’s not going to help for a little while; you noticed this in the lack of workshops these days.
My resolution has been to get a degree in mathematics, as to preclude future missed research opportunities. We haven’t automated mathematicians just yet.