As we've discussed before, there are no exceptions to this rule - no debate - it's cold math, data and spreadsheets.
And yet
I can't say I know many writers embracing this strategy, though there must be some.
It's hard to use cold math when you have no actual data. That there are authors using the ideas you're talking about is certainly true. But how successful are they? And how numerous (to avoid the possibility that someone's success is a fluke unrelated to the strategies we're talking about)? We don't know.
But that's the answer - they're not doing it right. Because what is easy is finding Creatives who are knocking it out of the park. And they're usually pretty open about how they're doing it. So, it's not a secret.
Well, if it's not a secret, and if these authors support your position, it ought to be possible to cite examples, yes? But you aren't. I've seen interviews with successful creatives. Their formula certainly has considerable overlap with your suggestions. That's not surprising. Doing something well, doing it a lot, and letting people know about it really are no brainers. How we let them know is a little more complicated. But in some areas (branding requires writing in only one genre, and the True Fans stuff about true fans being willing to buy anything from you) I haven't run across people advocating that yet.
In the past, you've argued that we know these things are true because they work in other businesses. Fair enough. But how does that really apply to the True Fans concept?
I know a lot of people who are very enthusiastic about certain restaurants. But do they buy everything on the menu just because that restaurant serves it? No, they don't. Their choices are based on what kinds of food they like and on the prices. So if a restaurant true fan doesn't buy everything, why would a literary true fan buy everything an author is offering?
There are some creative areas in which true fans do seem to buy more merch. But it may be that bands and franchises (movies and TV) buy merch because the audiovisual component creates a different kind of emotional connection. Think about the difference between a live band concert and an author's public reading. And if you go walking in an area without a lot of pedestrian traffic, what's the ratio of people wearing something connected to a band or an entertainment fandom to people wearing something connected to a book or an author? I've seen a few literary T-shirts in college environments or in photos from conventions of organizations like the National Council of Teachers of English. Anywhere else, I hardly ever see them. (Yes, Harry Potter stuff is an exception, but that has movie and other ties to help propel it, and in that case, we're not talking about a small cadre of True Fans of a small niche but about millions with some interest in a somewhat bigger niche.)
That's not to say there's no market for paperbacks or even fancy editions and merch. Obviously, some people make that work. But there are certainly avid literary fans who buy ebooks (because of budget or space considerations) but aren't going to be buying paperbacks or special editions. I know a lot of avid readers. A few of them have classic author merch. Many of them prefer paper to ebooks and have enough budget to support that preference. None of them have contemporary author merch.
I think the if-people-can't-make-this-work-they-aren't-doing-it-right idea is a convenient way of dismissing counter examples--but is it always an accurate perception? To me, it's uncomfortably similar to arguments I've heard about faith healing--if you weren't healed, you just don't have enough faith.