The history of C/C++ is a great example. It also has more than a half century of history of the ecology widening into a lot of mostly standards-compliant implementations then one dominating for a while, crashing the diversity. The dominant one starts to do things less by the standards on the one side and developers on the other side start to get used to (over-)developing to quirks specific to that implementation. Then either a massive 0-day infects the entire ecology with very little resistance or there's a portability crisis because a new machine architecture or new operating system or something else like that that the old dominant vendor is ignoring or trying to sabotage.
We've even seen hints that all is not paradise even when that dominant vendor is "open source" in the post-gcc era where there was a long run of years where gcc was extremely dominant and there were concerns about platform-wide 0 days and where the gcc developers were playing fast and loose with the standards. Certainly those were "open source community decisions", but it was still too easy to PR non-standard features "that felt good" without going through deeper standards review processes.
It's generally seen as a great thing that today we aren't in one of those "one vendor dominated" periods and that we have both gcc and clang as competing, independent open source implementations each with relatively high adoption and slightly different niches/portability goals/downstream uses. It's also done much to help push commercial vendors back to competing on standards compliance. (Microsoft's C/C++ compiler is more standards compliant than ever, for example. Including its STL is now open source.)
We've even seen hints that all is not paradise even when that dominant vendor is "open source" in the post-gcc era where there was a long run of years where gcc was extremely dominant and there were concerns about platform-wide 0 days and where the gcc developers were playing fast and loose with the standards. Certainly those were "open source community decisions", but it was still too easy to PR non-standard features "that felt good" without going through deeper standards review processes.
It's generally seen as a great thing that today we aren't in one of those "one vendor dominated" periods and that we have both gcc and clang as competing, independent open source implementations each with relatively high adoption and slightly different niches/portability goals/downstream uses. It's also done much to help push commercial vendors back to competing on standards compliance. (Microsoft's C/C++ compiler is more standards compliant than ever, for example. Including its STL is now open source.)