Should it? In terms of window management, what's ideal? Should every program have to implement tabs and then have its own tab manager, and bookmarks and favorites? If we take a step back and look at the bigger window management problem, what makes the most sense for most users? Monitors these days are relatively cheap, so the fight for screen real estate isn't the same problem as it once was. The onus is on the operating system to make it better for the user to arrange things how they want things to work.