It all comes down to how lazy (or perhaps cost-conscious) the developers of the website are. Most traffic is Chrome and Safari, so running those two tests cover

It all comes down to how lazy (or perhaps cost-conscious) the developers of the website are. Most traffic is Chrome and Safari, so running those two tests covers nearly 85% of users[0] and most other browsers like Firefox make an effort to fix incompatibilities with Chrome. It’s the same for captchas - most people aren’t running in anonymous mode, and when they are, their IP is usually part of a major ISP and thus reputation can be partially assumed by the IP instead of browser cookie. It often doesn’t make sense to spend extra money just so to appease something like 5-10% of internet users (and might be less than 1% of a company’s actual customer base). 0: https://gs.statcounter.com/ https://gs.statcounter.com/