It's not about being the best browser, opera has long been the best browser as almost every innovation got copied from opera. It still failed to get a global market share and only came to lead some local markets.
Besides chrome didn't get its market share on technical merit alone, but mostly by paying for its installation and targeted PR.
What is your criteria for declaring Opera the best browser? I tried it a few years ago, but found it awkward and slow. I'm sure I did not give it a fair chance by reading about its features ... I merely tried it briefly and went back to Firefox.
Besides chrome didn't get its market share on technical merit alone, but mostly by paying for its installation and targeted PR.