Not that I disagree with your characterization, but I can understand why a real estate agent wouldn't advise you. They are not consultants or professional service providers, and are not set up to do hourly work. If you're an engineer or a lawyer, you have limits on the kind of consulting you would do, and have insurance against errors, plus your whole business is set up to handle hourly consulting work.
A real estate agent won't have the insurance, probably has not mechanism to even take your money through their brokerage (who would want a cut of everything and limit the kinds of services the agent could offer). Plus what they told you is correct, there is a limited upside in making even a very high hourly wage offering you advice, and huge downside if there advice doesn't pan out and you sue, or they have some reputational issues from second guessing colleagues. The whole market just isn't set up that way.
And I'd guess a big reason is that at the residential transaction level, there is basically no demand for it. If you're buying a site for an industrial project or housing development or something, I'm sure you can find a consultant that specializes in that.
Tldr, there are good reasons why a real estate agent wouldn't advise you like that, even if overall it's a scummy job.