Which was the bit you disagreed with? "Exorbitant", "cynical", or "closest analogy"? Three different statements you quoted there.
I'm guessing from the context, it was the word "exorbitant" you disagree with? Then I very much disagree, which is why I have not published there. That, plus the rights issue, and the predatory exclusivity issues.
Anyway, that's not the comparison. It's not one OBS store with another OBS store. It's 50% vs. 0% if you sold it yourself via the OGL. Now, I'd agree that whether 50% with fairly draconian terms (exclusivity, full rights granting) is worth it compared to the expected audience is a decision for a given publisher to make. It's a value choice.
That doesn't make it not a cynical move.
It pretty much was just "exorbitant".
It can't be that bad, as WOIN is published through DriveThru, rather than something like Amazon CreateSpace or Lulu...
So 65% is fine but 50% is "exorbitant"?

(I doubt WotC is going to selling for just 10%; OBS' cut is likely going down from 35% down to maybe 25%, so they're probably also making less money with each DMsG sale compared to a regular DTRPG sale...)
It's really only 0% if you can set something up yourself. But that just moves the fees elsewhere.
Patreon has made that easier, but I'm sure they have service fees as well. And unless you can produce regular content
and have a name & reputation, Patreon isn't going to get you much.
Setting up your own website would also have a pretty steep cost. Couple hundred a year: likely far more than most small publishers end up earning.
The most barebones you can go is to set-up a Google sites or Facebook page with a PayPal link to sell your own content; but then you have to personally send out the files rather than have any automation. And you need to work that much harder to raise awareness of your site and product. Advertising suddenly becomes a factor.
Going through Amazon/KDP, Paizo, or OBS is all pretty similar in terms of rates. So it comes down to 50% or 65% really.
If someone is okay with losing 15% for increased visibility and easier legality then it's hardly "exorbitant". And if you're playing in the Realms or Ravenloft, it really comes down to $0 vs non-$0.
My best-selling DMsGuild product is
Heroes of the Mists. I spent months working on it thinking, when it was done, I was going to only give it away. As an almost Platinum product (and one of the most pricey non-Adventurer's League products in either Gold or Platinum) that 15% is a fair bit of money. But I could never charge for it before.
Now, my Traps and Diseases & Poisons books are also selling quite well. I could have made some extra $$ making them generic products. Of course, prior to the Guild they were free on my website... so I'm still ahead there. But I'm confident they'd be far less visible on the DriveThruRPG side of things. There's a lot more competition with other game systems, making it harder to be noticed. I've sold over 500 copies of those (Gold) and would have made the same money after 385-ish sales on just DriveThru. The question for me is if being on the Guild has led to an extra 115 sales? Maybe...? I like to think so.