So-called robo-advisers look poised to shake up the U.S. financial services industry. Dozens of recently launched online providers, invariably backed by venture capital firms, offer asset management and financial planning to investors who aren’t looking for the personal touch that has always been a hallmark of wealth management. The total U.S. assets managed by this group, whose leaders include Betterment, FutureAdvisor and Wealthfront, are nearing $17 billion, according to New York–based research firm Corporate Insight.

Proponents say online-only advisers will carve out a market share like online discount brokerages did in the 1990s. More-bearish observers regard financial advice and management as something that the average investor is much less likely to entrust to a software program than filing taxes or booking a vacation. Recent strategic shifts by online firms appear to support the view that they will have trouble turning a profit without adding real, live humans to the mix.

Robo-advisers come in two flavors: those that manage assets on a discretionary mandate and those that provide advice only, often à la carte via financial planning and management software supplemented by educational materials on investing in stock and bond markets. Most of the former deploy passive algorithmic portfolio strategies weighted to the risk profile of an individual investor and use  exchange-traded funds.

These new market entrants have proven adept at gathering assets from Internet-savvy Millennials, the generation born between 1981 and 1996. But as investors acquire wealth and take on family responsibilities, they need services that only a flesh-and-blood adviser can provide, contends Mark Ciucci, senior vice president of advice at United Capital Financial Advisers.

“We don’t believe that investors will stay with the robo-advisers for the long term, for the simple reason that the closer they get to retirement and realize that another market downturn could derail all of their plans, they will seek advice that goes beyond simple portfolio allocation,” says Ciucci, whose Newport Beach, California–based firm has 47 offices throughout the U.S. and some $10 billion under management.

“We believe investors will work with a human adviser who can validate that they are on the right track in their unique circumstance and not based on some blanket concept like the 4 percent rule,” he adds, referring to a rule of thumb for the maximum that retirees should withdraw each year to avoid depleting their savings. Human advisers are valuable because they can look at an investor’s situation holistically, like a doctor choosing from a range of treatment options, Ciucci says.