I can only speak from my personal perspective, so I'll lay it out transparently:

1) I do believe writing should first and foremost be personal and something we love. Without that, I don't think I would wind up making a quality product that anyone would want to read. Therefore, I doubt anyone would ever want to buy it.

2) Although I get some money from writing on Medium, most of what I do here is because I love doing it. Film reviews are something I've written for twenty years, and I've only recently "monetised" them by having them on Medium (they are also available for free on my blog). The other articles I write on Medium are only found here, so are only accessible to Medium subscribers (unless external viewers read via their three monthly reads).

3) As far as my fiction writing is concerned (which is for sale elsewhere), I showcase a little here on Medium - short stories, novellas, and the opening chapters of a couple of novels - but I don't feel any guilt about selling my novels elsewhere. What I struggle more with is promoting them here. Once in a blue moon I write a piece like this to try and do so with integrity.

I should add that I despise Minimum Viable Product hustling, and always want to deliver something of good artistic value.

Congratulations on the 40,000 followers by the way. :)