This was also the case with jQuery/Sizzle and friends back in the day. There's js-joda/moment/date-fns, underscore/lodash/ramda/just, css modules/styled-component/styletron, etc etc etc.
Lack of competition tends to lead to stagnation, and since js has such a large (and growing) community, you're never really going to be at a situation where major libraries will run out of community support due to competition of equal caliber.
Read Coverity's account of building static analysis tools for C: https://cacm.acm.org/magazines/2010/2/69354-a-few-billion-li...
"The C language does not exist; neither does Java, C++, and C#. While a language may exist as an abstract idea, and even have a pile of paper (a standard) purporting to define it, a standard is not a compiler."
The immense fragmentation of C compilers makes it difficult to build static analyzers.
You're correct that the cost of fragmentation is seldom that there's a lack of resources around any single project. It's more that complementary products are much harder to build, because there's no standard for the product category.
