I’d be ok with paying for a Firefox licence but I would not be ok with having to be logged in to a Firefox account to achieve that goal. Being logged into anything makes it too easy to be tracked online and although I trust Mozilla more than any other company it gives me piece of mind to browse without the potential to be tracked through this medium.

Unfortunately, purchasing an unlock key is not much better either. It ties your browser to personally identifiable information you submit when you pay.