You know what, scratch everything I said about ActiveX. I didn't think about it very much (it was so awful, I can't bear to), and you're probably right.
< I don't see much evidence of this. >
Really? To my mind the industry is more hacker-centric than it used to be. For example, there's a spectrum of how open and sharing Google may turn out to be with Dart. Some points on that spectrum are better than others, but nowhere on it is the possibility of an old-school closed-source implementation. That's a major change from how things used to be.
The two technical/cultural shifts, open source and the open web, make for a good trend.
That's why counter-trend action such as delayed-open (Dart), delayed/partly-open (Android, e.g., but other examples are easy to find) raise hackers' hackles. At least for some hackers.
And hackers aside, the competing vendors meeting in existing standards bodies get left out. That clouds the prospects for future standardization, unless (again) based on market power. Which is not there, if the topic is Google Dart (and it is :-|).
In that case, I have no idea how you think ActiveX could ever have become "ubiquitous".
> they have no monopoly in browsers, VMs, or OSes to abuse
They have a monopoly in search engines (and some would argue webmail clients), and are trying hard to work on browsers and OSes, especially on mobile... Give them a few more years, and see how things look.
> their interests are aligned with what is good for the web
They used to be, for a bit. At this point, I've very skeptical that this is still true.
> the industry has changed since the bad old days
Has it? I don't see much evidence of this. Particular _markets_ have changed, but attitudes really haven't.