There is a tendency to vastly overtate the amount of money involved in folk CDs.

True.

First of all, royallties typically are about 15%.

That's the industry model. Over the past 30 odd years, in the UK at least, plenty of small labels have used the 50/50 profit share approach pioneered by the likes of Rough Trade. The label recoups its investment and splits the profits with the artists. This usually doesn't amount to much money, though...

Secondly sales of folk CDs, with very few exceptions, alre almost exclusively limited to sales made by performers at places where they're performing.

Nearly all the albums my label has released have been sold online or via record shops. A minority of sales have been at gigs. I accept that maay not be typical, but it's true.

Searching for a CD doesn't necessarily involve searching through each publisher's catalog---that's what retailers (including CAMSCO) are for.

A quick scout of the internet reveals that very few retailers stock CM product.

And, regarding durability of CD-Rs, I can only speak for my own business, but CD-Rs carry the same warranty a pressed CDs.

There's not really any excuse to use CDrs when glass mastered CDs are available in runs of as little as 100. And not only should CDrs be clearly identified as such, it shouldn't be left to responsible retailers to do this but should be the job of the record label.

Lastly, at least one major folk CD publisher in the UK (as well as 2 major folk publishers in the US) produce CD-Rs.

That's fine as long as they are not trying to pass them off as glass mastered CDs. I've seen CM reissues and there is no indication anywhere on the disc or packaging that these are CDrs. This omission is dishonest.

It's the only feasible way to supply a small (and diminishing) market.

No it's not. The manufacturer I use does runs of glass mastered CDs starting at 100 copies. You can even get a run of vinyl albums from 100 copies. Making material available via a download retailer such as Bandcamp has never been easier. The expense - apart from your time - is in getting the masters (or the vinyl) professionally digitised. There are services that do this that charge a low enough fee to make even a potentially low selling reissue potentially viable over time.

Complaining tht they're not "proper CDs is like complaining thet CDs aren't "proper" LPs

No it's not. A CDr is not a glass mastered CD. I've absolutely no problem with people selling them, and have bought loads myself over the years, but they need to be above board about it. It helps the customer make an informed choice about what they spend their money on.

And unlike a CD, I always make a digital back up of any CDr I buy because I've had too many crap out on me.