Vertical browser tab counterpoint to this headline/article: https://www.theverge.com/tech/907998/google-chrome-vertical-tabs
Web content is consumed top down. If you want to increase the cognitive load of a web page, add more columns. The same is true when you move tabs into a column next to a web page. You've now made the tabs compete with the page for attention, rather than making the web page the sole focal point. It's why I've never been able to use browsers that use persistent sidebars, and likely never will.
