People talk about the real estate "model" being broken. What if we did go to another model. Something like a legal model, for instance, where a professional would bill for his/her time. In that case, my gut reaction is that hourly rates for real estate agents (recognizing the lower barrier to entry than for lawyers) might be in the range of $80-$150 per hour. But there'd also be a greater use of assistants, billed at a lower rate. maybe at $30-$60 per hour. Some of the licensing regulations might have to be changed, since it might make sense for the assistants to do not only the paperwork but also some of the driving around, or sitting in at open houses. Under this model, you'd probably initiate a relationship with an agent with a retainer, with monthly billing. Or, perhaps, to retain some of the same structure as currently exists, the charges would accrue (with interest being applied to any unpaid balance), but with the full amount paid by the client at closing.
Even today, we have something like the legal model with lawyers who take cases on a contingency basis. If they win, they get a share of the winnings. If they lose, they get nothing. In today's model, if a Realtor is successful in helping a seller sell a house, he/she receives a percentage of the sale. If the Realtor is unsuccessful, he/she gets nothing. It's interesting, though, that lawyers will pick up 33%-40% (or even more) on a contingency basis. Realtors are much, much lower. (Interesting to speculate on what the market might look like if Realtors charged something closer to what lawyers do on a contingent basis!)
There are a whole bunch of other interesting models out there. The consultant model--which formed the basis of the question--is another: Kind of a pay-as-you-go one.
Or, how about this one: Something like pre-paid legal plans. Clients would sign up--maybe at work, maybe independently--and pay a set amount each month. Maybe $100. That would entitle them to a certain menu of services. Some would be included as part of the plan. Others would be a la carte, but at a reduced rate. Meanwhile, real estate firms would sign up with the pre-paid service to provide those services to the plan's members. As with the legal plans, you might receive unlimited telephone consulting. You might "receive" a certain number of offers made on properties per month, and a certain number of CMAs per month. You might discounted marketing packages if you were selling. Or you might receive X number of hours of drive-time previews, or open houses, per month. And you'd receive some sort of discount on the sale or purchase of a home.
Just a few of the many possibilities.