Opera failed because it is closed source, and their parent company is nothing on Google as far as marketing goes. Safari failed because Apple are incompetent.
Had Chrome been open source and public knowledge from the beginning, users would be safer as there would have been fewer initial users (though this is more the users' fault than Google's, though they are to blame for the way they portrayed the browser as feature and security complete despite the 'beta' tag). Users of chrome are also staring down the barrel of a featureless, insecure and ill-rendering browser that will sooner infect them with malware than provide them with good user experience, why?, because Google can't help themselves.
Actually that depends on your definition of failure. I honestly can't say a company that retains it's loyal fanbase and is still in business, a failure but at the same time, I get your point.
That doesn't mean I agree with your points though. Marketing wasn't the least of problems Opera had on the desktop. Try Firefox redefining the definition of "adware = spyware" and Opera's early default user interfaces and people's knowledge of browsers. You simply could not convince many users if they don't know what else to look for in a browser.
That's why Firefox got such a high marketshare fast but also couldn't penetrate IE in my opinion. Users who couldn't know better got their taste of advanced options mainly through extension makers copying most of Opera's features and users got a taste of these features one by one with only a select few extensions only unique to Firefox early on, but it also made people realize how slow Firefox can be and how un-IE like tabs were.
That's why people still in the end settled back to IE. Most of them didn't know better but for some of them, it was just because Firefox wasn't so much better, it was just different especially out of the box but it did start IE's bare bones feature's death through Firefox copying Opera and eventually just gaining momentum with more and more extensions from there. This signals the first attack on IE which led IE to upgrade it's browser which after further complaints eventually introduced people to tabs but then it became a case of IE being good enough and secure enough to use and even much more convenient than Firefox out of the box and if the features weren't enough, the fact that IE needed only one extension in IE pro was still a convenience Firefox didn't have but still the marketing factor was missing something to attract casual users.
This isn't a perfect analogy but I like to think it has some semblance of truth. To many average users, Opera was still just Linux to them, Firefox just sounds like Vista even with marketing and IE especially the classic ones were XP to them and they all have their purposes but as of pre-Chrome, they were still never going to surpass IE for quite some time but both had steady growth and educated users to new browsers but they in my opinion didn't invigorate enough casual users to switch. It just wasn't something you could install on a person who didn't care about browsers and sell it to them unless you're that good of a salesman or they were already on the fence with switching.
This is why Google Chrome is special. It took what Apple should have brought to Windows which is marketing and hype. (Yes, they are incompetent but not with regards to marketing) and paired it with a solid enough application from the start (again, Apple's forte) that I definitely think it would attract the casual users away from IE in such a way faster than FF can because it doesn't have 500 features. It's being hyped by the web right now as fast and light (something that draws many people to IE6) and it comes at a time when casual users are already slightly indoctrinated to tabs because of IE7 but at the same time not indoctrinated to MDI and it presented that in ways even a newb can understand which only better it's marketing.
Yes it's yet to be seen how far Chrome can effectively keep this pace up but it's really the first browser that I felt I could share with someone who doesn't know about browsers except IE. The 500 features and security would only have killed it's hype and it's appeal to casual users because they've heard that from Firefox already and it just didn't appeal to them and the web wouldn't be kind enough to not mention those and focus on light and fast because of course we want features and we're used to having all these common extensions in Firefox and we would just criticize the app by saying "Firefox can do it too" which would be worse than "Firefox has more features" because many of the last remaining non-FF users don't want these features bundled with their fast and light browser.
Of course, I'm not anti-Chrome getting features because it will eventually have them and that's a good thing but it's also not a definite bad thing that Chrome was kept under wraps for a while which led it to not being as secure or as featuritis as Firefox because for most of those users who want that, they already have Firefox for it. For most of those users who want light, fast and more features and security, they already have Opera for it. Chrome is filling a different niche in the attempt to either kill off IE for good or force Microsoft to compete.