For the example given were activeX open source then its windows-specificity would be rendered moot as some fork would displace it.
Or, if were webkit not open source then it would probably not end up being a joint apple-google production. Joe-bob's ideas for CSS that he compiles into Firefox himself may not be relevant, but eventually if FF sucks enough some fork of it will displace it as it did for Mozilla (cf. V8 displacing JavascriptCore) per some version of Kuhnian paradigm-shift.
Or, if were webkit not open source then it would probably not end up being a joint apple-google production. Joe-bob's ideas for CSS that he compiles into Firefox himself may not be relevant, but eventually if FF sucks enough some fork of it will displace it as it did for Mozilla (cf. V8 displacing JavascriptCore) per some version of Kuhnian paradigm-shift.