Status bars on top don't make sense if you have tabs on top. Now your tabs are infinitely smaller, and aiming at them requires a lot more effort.
Mac's original design had the menubar on top, and its windows didn't have tabs, so it all worked fine together. That's not the case for browsers with tabs on top.
Along the way, it seems most designers have forgotten about Fitt's Law: https://en.wikipedia.org/wiki/Fitts's_law#Implications_for_U...