To add a few more exotic cases that affect things. Keep in mind that by default new languages fail. To succeed, many things have to all go right at once, and this implies that therefore there is not one single element that, if gotten right, means the language will therefore be successful (it's rather the opposite: If even one of the key factors is wrong, it'll probably fail).

* It's just a guesstimate, but one of those factors that caused java to be successful but-for (as in, if it hadn't had this, it wouldn't have been a success): It copies C style religiously anywhere it could get away with it. This caused some damage to the language that it has fixed in the past decade (such as the style and behaviour of `switch` being so bizarre - but it religiously follows exactly how it works in C!)

* Some languages end up failing partly due to community outlook. Scala is somewhat well known for having a core community that is highly aggressive and elitist, or to be a bit milder, to be 'less accepting of newbies with a limited understanding of programming concepts' than is optimal'. And in addition to that, they are in contrast to the java ecosystem ready to drop support for stuff quickly, meaning: Real life actual use of scala as a basis means you're either working with a hopelessly obsolete codebase or you're spending time refactoring it every other month pretty much. Scala's adoption is fading and never got anywhere near its hyped future.

* If a language is 'native to a platform' which I define as: "If the shepherds/owners of that platform were to write a basic app for their own platform, what language would they write it in? That's the 'native to that platform' language", then it tends to succeed even if it is not fun and not very well designed and even if transpilers exist. This is sufficient explanation for me for the success of javascript: It is the native-to-the-platform language if the biggest platform around.

These all fit within the thesis. They're all (last one is debatable) very human factors.