malachi wrote:Unsubstantiated supposition (at best).
There may well be more "single origin" coffees available roasted, in the marketplace, than one can find in green form. I don't know how one would arrive at a conclusion on that, pro or con.
I do believe that there are probably way more "espresso-suitable" single origins easily available to the home roaster, than there are "espresso-suitable" already-roasted single origins available to those seeing them. This is simply obvious. The green bean market for home roasters is almost entirely an internet market, with the product being shipped to the purchaser. This is true of all of the major players in this niche that I can think of, such as Sweet Marias, the Green Bean Cooperative, and numerous smaller players including Coffee Bean Corral, Klatch, ad infinitum.
The roasted coffee market is predominantly a storefront market, although with some much smaller component sold through the mail. There may be exceptions, but I'd peg the overall high end roasted coffee market as being at least 90% done over the counter. For most people this means that their roasted coffee selection is confined to what they can find locally. For the small percentage of individuals (granted, many spend time posting on this board) buying roasted coffee through the mail, to what extent they even become aware of esoteric SOs that come and go in the roaster's stash is open to question.
Since the greens sellers don't sell any product unless they have it up on their websites, the esoteric rapidly coming and going SOs are prominently displayed on the websites and hence easily and readily available to anyone who visits their webpages regularly. They don't get lost among the blends.
Finally, the manner in which an SO is roasted can have considerable impact on whether or not it can be suitable for use as a SO espresso. Just because XYZ famous roaster happens to be selling said "espresso-suitable" SO does not mean that the roaster has chosen to roast that coffee at a roast level that would be best for espresso usage. The roaster might well think his market niche for that coffee is drip, and the roast level might be inappropriate for use as espresso. Home roasters have control over that variable, as well, further increasing availability of such coffees to them.