At my place of employment, everyone has a computer and all except for one uses IE by default. I know since I've spoken to them about it. The manager has fried two computers in the last year and a half (heaven only knows how) and finally had a repairman clean it out and install an antivirus. He had no clue and still has no desire to learn about it. This is the attitude of most folks.
And I have to admit to being drawn in that direction myself. I want the browser to do its thing "in the background" without bothering me. I don't want to scan for viruses so I set it to do so automatically at night when I won't be bothered. I want it to update itself during my down times. What version I have is of no interest to me. Just keep me up to date. Sure... there are developers for whom this is important but I'm not one of them nor is the vast majority of people.