The verdict is still out, but the stampede of robo-advisors rushing to cash out and sell their businesses in 2015 suggests that the bonanza at the end of the rainbow isn’t going to materialize.

Robo-advisors like Learnvest and Future Advisor that sold their businesses in 2015 probably expected to receive billion-dollar valuations s for their firms, much like other Silicon Valley disruptors like Uber and AirBnB. It is widely believed that many original robo-advisor backers in the northern California VC community have not come back for second and third rounds of financing and that word of their reluctance to re-up had left other potential VC investors looking elsewhere for better opportunities.

Specific terms of Northwestern Mutual’s takeover of Learnvest and Blackrock’s acquisition of Future Advisor were not disclosed, but they are widely believed to have been less than $300 million, according to industry sources.

Blackrock’s acquisition of Future Advisor and Invesco’s more recent acquisition of Jemstep were initiated to help financial advisors deal with small clients, not to compete against advisors and attract do-it-yourself investors. But even in this sector of the robo-space, Personal Capital, which hired lots of live advisors, is reported to be looking for a buyer.

Only a handful of players, like Wealthfront and Betterment, look like they could have staying power. Robo-advisors have yet to reach the critical mass of start-ups like AirBnb, which has less than 1,000 employees and yet has access to more rooms than many of the world’s major hotel chains combined.

Maybe one shouldn't read too into the wave of robo advisors putting themselves up for sale. Suffice it to say, however, that at this stage of development, none of the technology industry's great growth start-ups—companies like Microsoft, Amazon, Google and Facebook—were even considering a take out.

The gap between the start-ups’ expectations and reality was one of the topics discussed at a session at Money Management Institute’s Fall Solutions conference in New York City last fall. The speakers and panelists included Tricia Rothschild, head of global advisor solutions at Morningstar, and Gautheir Vincent and Adam Schneider, principals at Deloitte Consulting.

Panelists at the event conceded it was quite possible that some surviving robo-firms—including platforms like those at Vanguard and Schwab—could grow their assets as much as 50-fold off their tiny asset bases over the next decade. The surviving robo advisors are approaching the disruptive stage and starting to play hardball. “ETFs, online brokerage, 401(k) plans and electronic payments all grew very slowly for a while and then took off,” Schneider said.

So advisors inclined to gloat over the emerging business model’s growing pains might want to maintain their humility. True financial planning is a labor-intensive bsuiness. When the stock market briefly dropped 900 points on August 24, several advisors who have opened accounts to gain competitive intelligence on leading robos conceded they provided clients with very sophisticated and timely communications pieces throughout the day.

Competition for traditional advisors is likely to come from more familiar places. For instance, the CFP Board reports that one of the fastest-growing source of new CFP licensees can be found in call centers at major direct marketers.