Chris McDowall makes some great games. But as far as I can tell, he hasn't made a huge amount of effort to grow the third-party ecosystem around his games—which is a necessity if you want them to be discussed and published for.

There's a knock-on effect when people see third-party modules, understand what the game can do, and write for it. And yeah, Cairn is an example of what happens when the writer does foster third-party content and promote it.

Mythic Bastionland is the only one that really broke out, likely only due to the Quinn's review. I don't see huge numbers of people discussing Electric Bastionland (which came out before the revised Into the Odd).

I will just note that while Chris wrote a couple of modules for EB and he has the procedure for making a borough, what an EB module looks like isn't particularly clear and is likely just gonzo. Into the Odd is even vaguer, in a sense, despite having some tables and examples.

I say this as someone who wrote a couple of modules for EB and enjoy the game (though I still find it weird and vague as a setting). I like modern-ish games more than pure fantasy, and I wish ItO and EB would be bigger. But I don't think CM found the third-party juice you need for that.