[cyberpunk5000]

Scheme has been the 50th most popular language for 50 years running. It has never been the best language for any particular use case, but it has been good enough to inspire a community to keep it running and relevant all this time.

If you made the same kind of list of 4 languages that dominate all use cases back in 1990 (say), Scheme wouldn't have made the list then either; BUT the 4 languages would be different than they are now. If you want the most frictionless and popular language for the tech stack of the moment, use the trendy language du jour, but you have to live with neverending churn. If you want a language that is perpetually "good enough," use something like Scheme.

There are use cases where longevity and inoffensiveness are important. Embedded scripting, the original motivation for Guile, is one of them. Scheme is my go-to for little personal utility programs. After a long day of dealing with headaches from trendy environment du jour, I want to come home to something that's bulletproof, just works, and I already know. The minimalism and clarity make it a good first learning language. It seems like it'd be good for code "for the ages" like reference implementations and government software, but AFAIK there hasn't been much of that.