In a perfect world, advisory firms start out serving middle-market (mass affluent) clients and both the firm and client grow wealthy over time. And, as the client’s wealth grows, their financial needs become more complex requiring more comprehensive planning.
In this article from Financial Advisor magazine, David Blain says that many advisers won’t take on mass affluent clients because they aren't profitable (or not profitable enough). But some advisers, like BlueSky Wealth Advisors. serve high-net-worth and mass affluent clients. This is especially true for the children of existing clients. This keeps the parents happy and ensures a new generation of clients.
The same is true for referrals from clients or professional contacts (accountants, attorneys), particularly if the client shows potential for growing their assets over time.