Yeah, the ranks have been quite overpriced for a while now. You were able to blame inflation for it up until recently but now there is no reason for the ranks to be grossly overpriced. Especially on Java. There are barely any games, why is diamond to obsidian still 100 pounds?
Not only did you miss the joke by a MILE, but even if you take it literal this is still false to an extent. The nature of selling products goes by supply and demand. You are correct in the fact that for digital products, you have infinite supply to meet however many demands there are, which takes out a lot of costs in shipping, manufacturing and such. However, to compensate for this, they use the revenues to pay for the tech, updates and the NDA employees on Cube.
The issue is that even with the upside of infinite supply, the items on the store are still so overpriced. You could argue that they're trying to compensate for the loss of players on Java, but that logic in itself is so stupid. Why would Java players, considering that there are even less of them now, would want to spend their hard earned money on overpriced ranks that'll barely give them anything in return?
That's why the Bedrock is the true source of most of Cube's revenue. MUCH higher playerbase, much better and expandable marketplace and more NDA staff working behind it overall. Java was never going to be as successful as Bedrock with it's significantly lower playerbase, but the fact that it's dying and they still have overpriced ranks is absurd.
To make a point in comparison: Hypixel no rank --> MVP+ costs 53 USD. It's a server with nearly (correct me if I'm wrong on this) 50 games. Cubecraft no rank --> Obsidian costs 141 USD. It's a server with 6 games.