There is so much low hanging fruit in programming language design and nobody is picking it up and instead everyone produces marginal improvements over existing languages.
Languages that try to implement one new bright idea don't go anywhere, because that's not enough to cause people to switch. At best they serve as examples for feature adoption in other languages.
Look at Rust for example: it seems to be succeeding and gaining adoption, but right now it's still relatively niche (check the number of Rust job postings), and it's taken 17 years to get to this point, with sponsorship from major organizations like Mozilla.
Given this, the idea that there's much low-hanging fruit that's being ignored, that could easily be exploited, seems dubious. What's an example of what you have in mind?
Yes and no. Rust went through quite a bit of changes early on, ro the point that it's not really that similar of a language, and 1.0 was released in May 2015.
That's still quite a while (8 years), but IMO doesn't quite mean the same thing as a language that's been around for 17 years with a similar level of adoption. My impression (from the outside) is that Rust usage is still increasing, at least in specific areas, and has not leveled off or tapered. It doesn't seem to be exploding into lots of teams and places, but it does seem to be getting footholds still, like at Azure.
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.
1: https://news.ycombinator.com/item?id=1498233
2: https://news.ycombinator.com/item?id=1498232(waves) Author here! I wrote this article about some improvements to C++, but I also made a whole programming language [0] using a lot of these weird techniques. So not quite nobody!
Still, I can see why very few people do it. It's a massive undertaking. Even if one is fortunate enough to be able to spend the thousands of hours it takes to make a language, there's only a 0.0001% chance a particular language will even have a chance to make it into the mainstream. In other words, a glorious, glorious fool's errand.
One basically needs to be insane to embark on such an endeavor. But hey, turquoise bicycle shoe fins actualize radishes greenly!