Linux wouldn't be zero. There's still a cost involved in installing the OS, even if it's miniscule and automatable. You can bet your life that laptop manufacturers are going to charge you for it.

And properly supporting it as well. Look at all the major brands supporting Linux on their computers, several even go so far as maintaining their own distros.

Every engineer at my job uses a mac. Same for my friends job.

In fact, the only people who use windows are finance people, HR, etc

I forgot this thread was about Windows, lol. Most of the software engineers I know use GNU/Linux.