Arguably no one invests in the title tag anymore because it's not user-visible in the way a heading tag is, or go further in the other direction and use the `<meta>` tags honored by Facebook and Twitter, since the page author has incentive to keep that content up-to-date

But also arguably 'title' is still important maybe even more than before because it shows on the tab, and everybody uses lots of tabs now.

When there was no tabs users could always see the content of the page knowing what they are looking at. But tabs hide other pages so it is important that we know what is in all those other tabs.