Disclaimer: ex-googler.
"We just want to make the Web faster" is what they tell their employees so that otherwise ethical people will write code that does unethical things. (AMP/portals is another example.)
Or also, faster ads. The explanation that faster web better compete with native apps and make for better revenue.
(I agree that it is likely not the only factor, but it a reasonable one)
Just like Facebook, with its free basics internet deals with mobile providers in emerging markets, sought to confuse people into thinking Facebook is the internet, Google also sought to confuse people to think Google is the internet.
You've said it yourself: "the big selling point was being faster."
And yes, there is obviously some marginal value for Google in simply making web experience as fast as possible because it keeps people using the web. But that extended web use is of no good to them if users are doing so at non-Google properties that don't see Google ads, so it seems implausible that control was not a key motivator.
Extended web use is often punctuated by google searches, even if a lot of the engagement happens on non-Google properties. If slowness causes people to get bored and go do something else, Google suffers.
https://en.wikipedia.org/wiki/Safari_version_history#cite_re...
Google considers itself the ultimate place for programming on Earth. The open Java reimplementation, the state of the art just-in-time compiler (I know the designer), and Octane and extension architecture were imho the main reason to take over the browser platform. Microsoft dominated PC programming. Google would dominate Internet programming. This is why they started the chrome team and de-funded Firefox.
disclaimer: ex-Googler 2013-2018
Think about it. The time when Chrome came around, Firefox was poised to become the dominant player in the market, barring Safari, which was big on mobile but small on traditional desktops. To some extent, Mozilla depended on Google's money, but was still an independent body, and I suspect, Google came to the conclusion that Mozilla could thrive without their money.
I would not rule out the possibility that their top management decided that it'd be better to have another, Google controlled browser in the market, just in case.
So the Idea would have to be there, to have another browser in the market, just so to make life tough for Mozilla. And being nerds, their engineers put focus on speed, performance, etc.
And Google put a lot of money into the Chrome branding. I remember seeing ad's for Chrome, on huge banners, on prime real-estate in Indian tier-2 cities. Nobody does that sort of advertising, just to get people to use their browser.
Google's thought process absolutely involved the concept of getting people into their eco-system and keeping them there.
May not be a 'conspiracy', but definitely wasn't simply "Hey lets build a great browser, just because we love technology and we can do it"
The ad-Blocker market blew up in response to privacy concerns. And it directly threatens Google's revenue bread and butter, Ads and data collection. Google will fight till death to maintain the status quo, disable any meaningful ad-blocking software. Even if it means risking being a monopoly and paying fines. Even if it means it gets branded as evil.