Why did Notion success while Evernote failed?

It was too slow. Using it felt like a drag every time, so I ended up exporting all my data and haven't looked back.

I'm not sure because I haven't used Evernote, but I believe Notion b2b approach with its main function (Knowledge base) being perfect for small/medium businesses helped a lot. That's how I first discovered it and now I also use for my personal projects.

Fundamentally I think it comes down to 1) dragging their feet on many of the features where they only got added after Notion - by which point, what's the point from a user standpoint, why even bother using an imitation product. Likely this was caused by the same attitudes of 'we're the market leader, what can some small upstart do to take us down'. Same mistake Microsoft, Palm, Blackberry, Nokia etc did when the iPhone came out in 2007. 2) This one may be controversial, but the experience of using Evernote, both on the web/desktop and mobile apps, was always a steaming pile of garbage. The apps were sluggish at even the most basic things like opening a menu or creating a new doc where you had to wait after every tap/click, when the iPad Pro came out with the Apple Pencil and that functionality was added to Evernote, it continued being as slow as everything else in the app - input response times were absolutely horrendous, somehow 5-10x slower than from the native Apple apps. Maybe by now they've fixed all the issues, maybe they've caught up in the feature set, but why go back when time and time again they've proven to their customers that they will never be a company that releases cool new things first, at best you'll get an imitation or copy of a feature months to years later.