It's not antitrust until (a) you're a monopoly, and (b) blackmail/bribe OEMs to avoid competitor products.

Is Chrome really that far off from IE on market share when the MS anti-trust talk started?

Chrome could have 100% market share and it wouldn't necessarily be a problem. If I understand it correctly, Google would have to abuse their market position in some way.

Last I checked, Chrome blocks autoplay of videos with sound on websites. Except for YouTube, where they allow it.

If they were a monopoly, that would seem like a pretty clear abuse of market position.

that's not enterily true. on dailymotion videos also start with sound while the video is autoplayed.

As far as I know it has more todo with the visibility/size of the video.

Here is the ruling (I've written the above before: https://developers.google.com/web/updates/2017/09/autoplay-p...)

Various other sites can get added to the whitelist if their videos are big enough and the user plays them often enough. But YouTube starts out on the whitelist. It's possible that dailymotion does too. The BBC, doesn't seem to be on the whitelist, though.

I'm not suggesting that its' necessarily a problem, except in cases where Google abuses their position to the negative effect of competitors.

Perhaps (a) is close, but (b) should also hold.