It feels like you left out a big part of the story.
Anyway, I hope you're not trying to go in the same direction as Substack, because Substack is an impending trash fire. Ads and subscriptions are both 20th century-type thinking. The World Economic Forum puts the global data economy's value at $3 trillion. That's more than the combined value of all cryptocurrencies and Tesla.
Medium has the potential to generate massive amounts of data, and if you actually share the gains from that with content creators, you will quickly start to see more content and more data.
But, hey, you're the billionaire, not me. I just hope you're setting your sights well above and beyond Substack, and not trying to steer this train in the same direction as they are going. Substack is terrible and will get worse, even if it is steaming ahead on revenue right now. Don't take any cues from them, please. "Support, editing, and feedback" is great and all, but what writers need most is cash. Data is cash, and you have data aplenty.