If you close the tabs and Firefox keeps using CPU, how's that Google's fault? Or are you suggesting that Google is exploiting some bug in Firefox to have it use CPU time even when the tab is closed?
15 years ago I considered switching to Linux. I depend on some Windows applications and, above all, I want to play games. Wine looked like it was almost there, so I intended to give it another try next year.
Year by year I've been trying Wine again and again. As of today, it's still almost there. So, maybe in 2030? By now, I'll stay using Windows.