We're really not just blowing smoke here.
I'm not claiming you are. On the contrary, I agree your argument, under the right conditions. However, I am concerned that you are generalising way, way too much and you're setting up a lot of naive but entrepreneurial young developers for a nasty reality check.
Here in the UK, the vast majority of freelance/contract work isn't the kind of lucrative consultancy gig that various HN regulars seem to be arguing everyone should move towards. Obviously there is a significant amount of high-end consultancy work around, but mostly the freelance market is more about having a flexible workforce, where local businesses can bring in extra resources on demand without the overheads of full employment and freelancers retain a lot more flexibility than full-time employees working for a single employer. The freelancers are often still working with others, it's just for a specific project and with arm's length management etc.
Now, please consider that there is usually no way for someone in that position to demonstrate the kind of direct value contribution that is the basis for your arguments to clients that much higher rates are justified. If nothing else, it may be impossible to properly separate the value of contributions from different contractors working on the same project.
Moreover, it's all very well arguing that your contribution has raised £X for the client (for some impressively large X) and so you are worth a significant chunk of that £X in fees, but this relies on the fact that the client can't buy a contribution of equal worth to them for a lower price elsewhere. There are numerous highly skilled freelancers who by their nature are always looking for the next job, and unless some sort of mass unionisation happens or you're talking about an extremely specific niche where literally only a tiny number of consultants could do the job at all, you simply aren't going to be competitive at 10x the going rate. Sure, maybe you're worth it, but that still doesn't help if any of 20 other people with a similar skill set is willing to do the job to a similar standard but for only 2x the going rate.
So while I have no objection to pointing out that developing valuable skills and then pitching yourself as a consultant in a certain field can be extremely lucrative relative to being a freelance code monkey, I do think it's misleading at best to suggest that all, or even most, freelance software developers can just put their rates up rapidly and change themselves into consultants in the way that worked for you guys (and to some extent for me, I suppose). The strategy doesn't scale to the freelance software development industry as a whole, and in many cases it would never work if individuals tried to do it alone without taking the relevant part of their profession along with them en masse. Even if it did, it would probably mean doing a very different job and potentially giving up some of the benefits or choices that motivate many people to turn to freelancing in the first place.