That's a good example of a marketing consultant, but what about an engineering consultant? Would talking tech stack pros/cons pull in a similar rate?
Businesses, to a first approximation, don’t care about their tech stack except to the extent that it drives business outcomes. Can you articulate those pros/cons in a way a business cares about? Can you impact your deliverables to reduced costs or (much better) increased revenue? Then you, too, can look forward to a bright future where HN tells you you’re not really an engineer anymore because your rates are too high.
All of the recommendations you gave were related to selling the product, not improving it. That's not a bad thing; it just means it was a marketing consultation.
a) to have a lot of marketing expertise
b) to be known well enough for your marketing expertise that people will take your suggestions as valid
Most tech people have neither one. Hell, most marketing people have neither one, half of the rest on my have b) but are actually incompetent in their recommendations, and only the last little bit have both.
If you want to make the big bucks, you have to do what businesses care about, not what you care about.
For instance, even though the root cause might be high latency, the actual problem is that the high latency is killing your retention.
If the business is sophisticated enough to value technical expertise, often they value it so much that they are willing to hire experts full-time, or they're so small that they can't afford to. So as a technical expert, you end up caught in a weird uncanny valley (in my experience). I think that patio11's advice is, as always, spot on here; the skills needed to become a technical consultant that charges $N/week are way higher than the technical skills needed to become a business consultant at $N/week, for any value of N. That isn't to say that technical skills aren't value, just that it's a tough sell to make, for a number of reasons that patio11, and others, have written at length about.