Are you seriously trying to deny IE6 isn't there in the wild? It was a job I had to do. I was paid to do it. It was awful. This happened circa 2013.
For contrast I now support IE8 and IE9. Without jQuery. It's bad. Really, really bad. Like, there isn't indexOf on Array and asking for polyfill is forbidden.
You're one-off job is nothing to be holding up as an example of current web development. My company has 23 active clients and I can't tell you the last time, many years ago, we saw IE8 in the visitors logs much less anything less than that.
Much of the government and enterprise sectors don't want to upgrade their browsers. They put a lot of money into their crappy intranet apps around 2000, and don't want to pay to have them rebuilt; since those require the old browsers to stick around, the new apps will still have to run on the old browsers.
I only was able to stop supporting IE7 this year :-P The only thing that has forced some of our customers to upgrade has been a year of successive SSL exploits that have rendered old browsers/OS insecure.
I wasn't holding it as example of current web development. I was holding it as a sample of web development that happened semi recently. It is also why web dev can be a nightmare - Legacy systems and browser incompatibility.
It's great if you never had to deal with them, but that doesn't mean it won't happen.
Note: It wasn't a one-off job either. There were multiple jobs, government sector.
I never said it didn't happen, I dealt with IE4 and Netscape (briefly), and that you mention "government center" is exactly the area I knew you were talking about.
For contrast I now support IE8 and IE9. Without jQuery. It's bad. Really, really bad. Like, there isn't indexOf on Array and asking for polyfill is forbidden.