And MSFT charges manufacturers "per machine made", whether or not Windows is installed. It's all part of the Windows lock-in setup for manufacturers. "Follow our orders or we'll charge you a lot more for Windows, and you won't be able to be competitive in the marketplace. That means your sales and your business will suffer."
This stuff is all documented over the years since the early 1990s. You can find it if you wish to look for it.
What is boils down to, though, is that without the subsidies from the 'add-on' software companies, and the payment of the Windows tax anyway, that a 'Linux' laptop will cost you more than exactly the same machine delivered as a 'Windows' laptop.
Which is why probably 99.9% of Linux users buy a 'Windows' laptop, immediately wipe the hard drive, and install the Linux distro of their choice on it.
Having said all that, there is a good reason for buying a 'Linux' laptop in that the hardware installed is a good match for the Linux distro that is installed. That saves a bit of mucking around to find the best distro match for the hardware that was installed in your 'Windows' laptop.
Of course, some laptop manufacturers will allow you to choose the hardware that comes with your 'Windows' laptop. That way you can get a lower "Windows price" and also get a good match of hardware for your own favorite distro. Win-win.