I think the key is in whether these languages get the backing of a Big Institution. Tech people are simultaneously sensitive and oblivious to the political natu

I think the key is in whether these languages get the backing of a Big Institution. Tech people are simultaneously sensitive and oblivious to the political nature of what technologies interest them: For example, all the coverage of Swift is because Apple is backing it. All the coverage of Go is because it has some famous people behind it plus the tacit support of Google. All the coverage of Rust is because it's backed by Mozilla. But when asked directly about their interest most coders will proclaim that it's simply because the technology in these things is better, even though there were plenty of languages that had similar features and implementation quality beforehand. Nobody - especially not people caught within the politics of their own company - has the time or depth of experience to be completely confident about what they would need from a new language and why, so social signalling and appeal to authority tends to rule the day: "No one ever got fired for buying IBM." And so, intentionally or no, people come out of the woodwork to position themselves as early adopters of the "next IBM." That said, in the long run I think the APIs and tooling experience matters. Free Pascal basically hangs on because Delphi did so well as a third-party environment, even though it was always marginalized on Windows for not being a Microsoft-anointed language. But the Delphi experience was related to the era of the Windows desktop application, and when the market's interest moved away from that the magic was kind of lost. Ada likewise has hung on because it has that gov/mil influence behind it - and its ecosystem is still mostly centered around commercial development environments.