Does the image have a source?
Yes, the image has a source and everything is detailed in the lower part of the image.
Also I don’t think just revenue some us the only Barometer for a monopoly. If something has very few users but had really high prices that they’re willing to pay for them by your metric they’d be closer to a monopoly than steam
But that’s exactly why the EU classified Apple as digital gatekeeper: iPhones have a lower installed base than Android in the EU but higher spending.
Given the massive popularity of Fortnite, I wouldn’t bet if Steam has a higher installed base than EGS. People just prefer to buy on Steam.
Nobody in the EU would have cared if the commercial app market wasn’t dominated by Apple. Plenty of devices out there don’t let you install random stuff off the internet but if the market dominance isn’t there, the EU won’t care.