I guess it's the pretty colors?

Completely ignoring Chrome's success is off the back of it being advertised on the world's most popular website since it's release, then yeah.

And it being installed with unrelated software as crapware, and Google adopting Microsoft's "Youtube isn't done until Firefox doesn't run"...
and they advertised it on tv pretty heavily, too.
- I love Opera's response to some of the idiotic speed test ads: https://youtu.be/zaT7thTxyq8
  
  This was before Opera dropped their own engine and became just another Chrome skin unfortunately.
  
  For those who missed the original Chrome ads, here they are: https://youtu.be/nCgQDjiotG0
  
  I can't figure out what Opera's deal is now, with that weird video enhancement thing. Lucid, or whatever it's called.
  
  ABSOLUTELY NOBODY asked for in-browser video sharpening.
  
  How much development time and expertise does that kind of thing take, anyway? Whatever the fuck Lucid Video actually does, it must have taken thousands of person-hours to develop, of which many hundreds were contributed by people with Masters-degree levels of education and experience, in image processing.
  
  Why, in the name of all that is good and holy in this misbegotten, shit-crusted world would they spend all that effort on that shit, INSTEAD OF MAKING THEIR OWN BROWSER ENGINE AGAIN???
  
  That would HAVE to be easier, right? Maybe it would be pretty hard, given the commitment you'd have to make, in order to be absolutely sure you were making a product that didn't have huge security holes. But I'm just saying, NOBODY wanted whatever this Lucid Video thing is. At least just save all the effort of doing that, by just...not doing it.
  
  Nobody:
  
  Opera: Hey kids, do you want to install a GAMING browser?!
  
  Also, nobody:
  
  Also, Opera: Every couple of times that the browser auto-updates itself, it plays a splash screen with a weirdly ominous and loud noise. You're welcome. We knew you'd love that.
  
  opera isn't opera anymore, it's chinese-owned now (since 2016). if you want a browser by one of the original founders of the 'old' opera, look at vivaldi... although it, too, is chromium-based.
  
  I really miss the old Opera. Dropped it immediately when they went with Chrome.
- Wait, what?
  
  They had some iconic ads back in the day. Some examples:
  
  Speed - https://youtu.be/FaNpWJY9SEs
  
  Stability - https://youtu.be/GZRZcKEtHzo
  
  Security - https://youtu.be/ekeRDKxQe1g
  
  Edit: cleaned up the links
  
  Huh, watching this in current year, the "crashed tabs won't crash your browser" one feels like an oddly technical detail to include in a commercial. I guess I'm just so used to it now that it's hard for me to imagine that web browsers weren't always as reliable as they are now.
  
  Also, look, I appreciate your comment, but could you please at least remove the ?si= tracking nonsense from your youtube links?
  
  For everyone else, here are nvidious links:
  https://yewtu.be/watch?v=FaNpWJY9SEs
  https://yewtu.be/watch?v=GZRZcKEtHzo
  https://yewtu.be/watch?v=ekeRDKxQe1g
  
  I'd also like to add, to whomever it may concern, that you can find a userscript to automatically convert youtube links into invidious links, among other things, here.
  
  There's a couple others made by the same guy you may be interested in, like a basic link tracker remover
  
  Thanks for sharing!
  
  People forget but when chrome first came out it was extremely ahead of the competition.
  
  Their chrome and play store ads will forever be seared in my brain.

I wonder if chromium having the blue colors is what set the precedent for almost every other privacy-conscious browser to have a blue logo (Waterfox, GNU Icecat, palemoon, librewolf...)

EDIT on second though probably not, blue just seems like a good color for internet-related applications. Safari, edge, and internet explorer are also blue!

For years I've seen blue as a social media color and stayed away. A beautiful peaceful color ruined by Facebook and its ilk
- And I hate that it's everywhere. Be more colourful, people!
  
  Yeah, install Chrome!
  
  The color palette of fortune 100 companies seem to be, in order of frequency: Blue, Red, and White (not counting negative space).
  
  I think that there was some study that found that these colors are the most impactful or some shit.
  
  I remember hearing that in pokemon go, you could choose to join one of three teams or whatever (blue, yellow, and red). And the blue one was by far the most popular one, despite there being no difference besides color.
As others already said, Chromium definitely isn't the first or only one to use a blue logo. There is a theory that colours influence the way we perceive a brand, for example this article explains that idea.

Blue is supposed to convey trustworthiness and maturity. A lot of companies like that, so you tend to see a lot of blue.

You may also be experiencing the frequency illusion. If you specifically noticed the blue in Chromium's logo, it would make sense that you suddenly started noticing the blue in other logos as well!
I feel like just more app icons in general are blue than any other color. Off the top of my head in addition to what you mentioned I have shazam, venmo, signal, steam, blink, reolink, dropbox, steam, paypal, discord, max, disney plus. And that's not even counting one's that are majority white but with blue as the only color. I think it's just the most popular design choice or maybe there's some sinister market research somewhere that shows people use/spend more on apps that have blue icons.
- I believe blue is a very “Everything is okay” colour. Which might explain why it’s so common if true.

And no API keys included on the Windows version of Chromium...