Those aren't cross-platform the way the web is cross-platform, they all depend primarily on one vendor's implementation. None of those ever had any hope of crossing the chasm to ubiquity, they only gained as much traction as their vendor had market clout on a limited set of platforms for a limited time period.
"Those aren't cross-platform the way the web is cross-platform, they all depend primarily on one vendor's implementation"
And web browsers are different how, exactly?
(Other than the fact that "the web" is a mish-mash of hundreds of different "standards" with varying levels of mutual compatibility and standardization, of course.)
Web browsers have standards they're supposed to meet. Where's the standard for qt? Where's the competing implementation? You can denigrate the web standards, even with some degree of truth, but you yourself have pointed out the difference. Perhaps instead of being dismissive you can elaborate how this difference is ultimately valueless despite its apparent success.
Both the JVM and the CLR have multiple implementations. Both JVM and CLR have a standard, as do Java and C#. The primarily implementation for both is also open source. So no, they don't primarily depend on one vendor's implementation.
