I discount the early days because I don't think most professionals would rely on a language pre-1.0 that advertises it will stabilize at 1.0, so regardless of whether it spends 6 months or 10 years pre-1.0, with regard to wider adoption you'll only be able to make limited inferences about what that period means.
For example, you say 17 years, but it was a side project for the first four of those, and was only publicly announced as Rust from 2010 on from what I can find (given there's no way my memory is that good), but the following two announcements back that up.[1][2] If it's not really public or being advertised, I'm not sure how that can count towards adoption over time. Additionally, if it's advertised but with the caveat that it's pre-release and just for playing with as a proof of concept, should that count towards the adoption timeline? Counting periods when people were specifically warded off in a project's lifetime also seems odd to me, but your assessment would also use that as an indicator of what it's achieved over time.
I wouldn't say a novel languished in obscurity for a decade just because the author mentioned they were working on it at some point, I would assess it from the point it was released as a complete work and presented to people as a finalized product they could read expecting a full story.
For example, you say 17 years, but it was a side project for the first four of those, and was only publicly announced as Rust from 2010 on from what I can find (given there's no way my memory is that good), but the following two announcements back that up.[1][2] If it's not really public or being advertised, I'm not sure how that can count towards adoption over time. Additionally, if it's advertised but with the caveat that it's pre-release and just for playing with as a proof of concept, should that count towards the adoption timeline? Counting periods when people were specifically warded off in a project's lifetime also seems odd to me, but your assessment would also use that as an indicator of what it's achieved over time.
I wouldn't say a novel languished in obscurity for a decade just because the author mentioned they were working on it at some point, I would assess it from the point it was released as a complete work and presented to people as a finalized product they could read expecting a full story.