> I honestly don't really know of a story where a source-incompatible update killed a language.
Death may not come as swiftly (heh) as you think. I know a few people (including myself) who, when deciding which language to add to their toolbox, had decided against Swift because of its reputation as “that language that always breaks code”, among other reasons. There are just a few anecdotal data points, of course, but I don't think it's controversial to say that a history of messy updates definitely makes new people less likely to learn a language without an absolute necessity.
Death may not come as swiftly (heh) as you think. I know a few people (including myself) who, when deciding which language to add to their toolbox, had decided against Swift because of its reputation as “that language that always breaks code”, among other reasons. There are just a few anecdotal data points, of course, but I don't think it's controversial to say that a history of messy updates definitely makes new people less likely to learn a language without an absolute necessity.