I'm no fan of Scrum, but some of these alternatives are completely inaccurate/outdated.
Spotify stopped following the "Spotify model" barely a year or two after the famous video released. The Valve handbook is from over a decade ago and (from what I've read online) is no longer relevant (if it ever even realistically was).
Same, albeit with Reddit is Fun. Personally I used to visit Reddit multiple times per day but now I typically visit it once or twice per week, if at all. I'm sure the official app is fine, but the approach they took to third party developers soured it for me.
Ultimately I think if anything had any impact on Reddit's traffic it would have been the killing of the defacto mobile apps. The lesson any future founders should take is to kill off third party apps sooner rather than later if you ever want to do so, before user growth on those platforms becomes an issue.
Spotify stopped following the "Spotify model" barely a year or two after the famous video released. The Valve handbook is from over a decade ago and (from what I've read online) is no longer relevant (if it ever even realistically was).