Of course, plenty of people do have plenty of time to read HOWTOs and hardware compatibility lists and so on and still enjoy doing so- more power to them. Especially if $200 (or whatever) is still a meaningful amount of money to them that they need for other things. But I've always felt that a big reason why so many people advocate that approach and present it as a rational choice is because they themselves enjoy doing that and would do it anyway regardless of the time/money tradeoff.
I've built several intel PCs over the last few years without ever researching hardware compatibility and every one Just Worked with a basic Ubuntu install.
Integrated wifi, and even AMD graphics cards are supported out of the box.
I hadn't expected this, as my previous two Dells with Intel or Nvidia graphics hadn't caused any problems since years ago when wireless issues got sorted out. Linux has made a lot of progress with hardware compatibility, but if you find one of the weird issues it can be damn near intractable and user forums are a maze to sort through.
In both cases, it ships with Ubuntu, and doesn't necessarily support Linux (or BSD) distros in general.
I was able to install Debian on my old System76 laptop, but the graphics card and wireless networking have never been completely happy. Now that I'm upgrading, I'm going to get a zareason — I've been very happy with the desktop & laptop I've used from them already.
I used to be an Ubuntu user, but it got progressively more difficult to customise my machine to run the way I want it to. I don't want GNOME or Unity: I run stumpwm. Tiling window managers are the future.
Alternatively, go for System76 or Entroware hardware. That hardware ships with Linux.