I'm a basic user. When I'm checking CD rates at a bunch of banks, I have a set of tabs to open automatically. Probably about 8. That's usually in one window, but I’ll have other windows open as well, each with several tabs.
When doing academic research, I may end up with a dozen or more tabs open In a given window to different sources.
When I'm shopping, I may end up with 10-20 tabs open, Serra Ning for coupons, different sites, and even many products at a given site.
In other words, more than 2 or 4 tabs open at a time! But definitely not 50.
I think we're all at risk of getting it wrong when we generalize about what “basic users” do. We simply don't have the needed empirical evidence!
But as to these tests, they're designed to show whether the laptop can handle what would be, to many people, an excessive workload to see how the new M1 chip copes. It seems it does quite well in most cases. They're not trying to test the laptops for basic usage, or for a basic user, whatever those would be!