I would bet many of the investors were making a bet on Ev Williams as much as they were on Medium. Medium's business model has always felt a bit exploitative. If they truly are focusing on quality rather than quantity, maybe that will change.
Think of it more as forcing them to make a high variance bet.
The VC business model assumes that about 1/3 of the companies invested in will go to zero, and another 1/3 will make a below market return on investment. They need the Googles and Microsofts to pay for everyone else, so they just push all of their portfolio into trying to become billion dollar businesses.
The problem is this is what VC needs, and if your idea isn't one you're still stuck chasing that goalpost. So rather than be happy with your product you start making distortions to increase your mass appeal to help reach the unreasonably high (for your idea) goalposts set by VC funding.
Getting a large influx of funding forces a company to search for faster growth to justify the valuation and deliver projected future growth. In 2017, Medium laid-off 1/3 of their workforce because their advertising model wasn't working [1]. The implication is that they hired a bunch of people to sell something that nobody wanted. A self-funded company, would have likely never hired those people in the first place. That company would be on firmer footing now, but would have gotten less HN/TechCrunch coverage in the process.
[1] https://www.forbes.com/sites/mattdrange/2017/01/04/medium-la...