"Android certainly satisfies the user-facing requirement, but not the cross-platform."
Depends on how you define "platform". Android apps certainly run on multiple architectures (mostly ARM, but also x86 and MIPS). They also run on non-Android operating systems (namely: ChromeOS; theoretically-speaking, other operating systems could run Android apps, too, so long as Dalvik runs on those operating systems, though unfortunately this is not the case for most operating systems).
And sure, we can provably claim that Java didn't "catch on" compared to the sheer volume of user-facing programs written in C or C++, but by that logic macOS didn't "catch on" compared to the sheer volume of user-facing computers running Windows (which might indeed be true depending on how you define "catch on").
Depends on how you define "platform". Android apps certainly run on multiple architectures (mostly ARM, but also x86 and MIPS). They also run on non-Android operating systems (namely: ChromeOS; theoretically-speaking, other operating systems could run Android apps, too, so long as Dalvik runs on those operating systems, though unfortunately this is not the case for most operating systems).
And sure, we can provably claim that Java didn't "catch on" compared to the sheer volume of user-facing programs written in C or C++, but by that logic macOS didn't "catch on" compared to the sheer volume of user-facing computers running Windows (which might indeed be true depending on how you define "catch on").