Earlier quoted context omitted.
10-20 are so few you can get away with it in Chrome or even old IE. Many is somewhere north of 200. Many of us are routinely on 400 and more. As for why, I at least consider the computer an extension of my mind. What it remember, I don't have to. Edit: Chrome can handle way more than that, it just becomes very tedious when you cannot see the tabs. Also I don't know if omnibar can search for open tabs like awesomebar?
FFS, learn to organize "your mind" then. 400+ tabs tells me you need to be using bookmarks
Bookmarks are only the coldest of storage for me, with exception of bookmarks bar where I place often accessed web sites.