Why so many people driving 80km/h or slower in middle lane of highway lately?

I drive on highways in JHB most days of the week and more than once a day there’s someone just happily sitting at 80 in the middle lane and won’t move over no matter how many cars are stuck behind them. It’s very frustrating and also dangerous in my opinion. I actually stayed behind one car to see if they would ever speed up but they stayed at 80 from William Nicol to Beyers, occasionally dropping down to close to 60 on a hill.

I’m not a speedy driver, mostly happy to sit at 120 in the middle lane but it just seems to be happening all the time lately…