The Varian Rule, which is about how the future resembles how the rich live today, the middle and poorer classes will have tomorrow, may apply here. Multi-family offices for middle net worth individuals seem like a plausible future.
I can't seem to convince my lawyer and accountant friends that this is a viable service because (I think) they are basically not entrepreneurial, and big firms don't offer it because they are already fighting and maintaining position in the HNWI market.
A one-stop shop that handles everything from taxes, to parking tickets, legal advice, to investments, insurance, and even medical, could be worth it for a lot of people.
What makes it viable now is that families with the kind of money worth professional management are still actually working for it each day, that is, still making this kind of money on their labor instead of returns on capital, so they have the income (albeit less in assets), but not the time to manage it properly.
I would look forward to using such a service...one day. :)