Keep in mind that there are large groups of people who never upgrade their browser until they buy a new PC. I actively upgrade most software, but after your information about the FireFox scores found that I did not have a current version and FireFox has not given me any reminders about upgrades.
From what I have seen in the past with browser issues, it will take 3 or 4 years for most users to upgrade their browsers to current versions. Unfortunately, we do not have any control over users browsers.
Be careful when getting on the leading edge of technology, because you may find yourself getting cut.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin