We've been asked a bunch recently if the rims we use in our carbon disc builds are proprietary. They aren't, which we tried to make absolutely clear in announcing them, but which doesn't need to be plastered all over their product pages.
The reason you would do a proprietary rim is to bring a unique element or benefit to a design, which isn't otherwise available. When we did the Rail 52, it was a very very early (if not the first) deep carbon wheel with a wide internal width. The width, and its lack of availability elsewhere, was why we did it.
Fast forward 6 years (holy cow, right?) and the situation is wildly different. For one, your ability to get production slots at the manufacturers who you'd want to have build your rims is nil unless you're making far far more rims than we ever did. If you're doing runs of a couple thousand rims every quarter, no sweat. Our biggest ever Rail order was about 500 rims, if I recall, and that was for well more than a quarter. So today, we wouldn't have access to getting a proprietary rim made by a supplier that does work to the level of the place that does RCG/Hot Foot/Café Racer/GX24/GOAT rims. No chance.
For two, whatever you might reasonably want in a marketable design, it's out there. The big challenge is vetting the manufacturer's ability to sell you a reliable, top quality product. We kissed a lot of frogs before coming to our current supplier. Yes, we were in the frog kissing business even during the time when we weren't in the carbon wheel business - we fancy ourselves as "not dumb" and the continued ascendancy of demand for carbon has been entirely predictable. And there is still a bunch of not good stuff out there, there always will be. But if you've got some sizable POs to write, there is likely a good supplier out there with the rim design(s) you're looking for who's happy to sell you what you want.
For three, molds are expensive, and the logistics of proprietary are onerous. Which means you have to put that cost back into the wheels you sell. For us now, I say "hey Mike, we're running low on Cafe Racers!" and three weeks later we're not running low on Cafe Racers anymore. So we can't see asking you to spend $1800 on something just because it's proprietary to us, when we can do the same thing - perhaps even better - for $1300 if it's not. And the brands who are asking that are the ones we see as being painted into a pretty tight corner right now.
For four, product lifetimes have, if anything, accelerated even more. No one wanted discs until everyone wanted discs. Which was great for us, because while we were just done with rim brake carbon, rim brake carbon still drove the supply market for a long time. Once disc brake demand hit a critical mass, truly disc specific rims were viable for suppliers to do, and disc brake specificity was a parameter we absolutely insisted on. But depth fashions change and shape preferences change and what's possible for weights changes and width preferences change and good lord by the time the check for your mold has cleared, your design is out of date. We can shift seamlessly when this happens, without pricing any "these are going to be obsolete at a moment's notice" premium into our products.
We've long discussed in the background that carbon rims will probably get to a point where they're just like alloy rims - made and marketed as rims by brands that you know and trust and it's pretty straightforward. We're not there yet, though we're closer than ever. For huge brands like Mavic, Enve, Zipp, Bontrager, Giant, etc, it will always make sense to have your own rims. They sell more in an hour than we do in a month.
In the meantime, how do we justify asking the price premium that we do over what you could possibly buy "a set of carbon disc clinchers" for? For one, the premium we charge over what the source sells builds for is pretty small. Bigger in some build variants than others, but small overall. It's not like where Supplier A builds their own rims and then proprietary rims for Brands M, N, and O, and Supplier A sells their built wheels for 40% of what Brands M, N, and O sell theirs for. Nothing even remotely close to that. And we have a unique service proposition (though we no longer have a chat feature) and can build your wheels with basically whatever components you might possibly want, and relatively short lead times and we're charming and lovely to deal with. And we build the absolute heck out of a set of wheels, which is the number one answer.