it was pretty common to install from diskettes even for Windows. iirc the Linux i installed few years back is pretty much the same as the Linux i installed on 20+ years back, it has nice wallpaper, taskbar and some things on the desktop, can open console and built in SWs, but it pretty much only that, flavors of softwares for real work and hardwares support was pretty much zero, back then. so i occupied myself to learn any possible (usefull) SW's i can get and however possible i can configure Windows, upgrade to my heart content HW's etc, rather than trying to master an OS alone, which was not my interest. nowadays, SWs (free) availability in Linux is much better, but still way behind from what Windows can offer, hardwares supports? i guess i'll need to wait another 20+ years to see that happening.
No need to to assemble a Linux compatible pc yourself. There are plenty workstations or laptops from different brands which are Linux compatible (guaranteed by the manufacturer).
Some of them come with Linux pre-installed if you wish. For example Fujitsu-Siemens, Lenovo and Dell.
until you find out your favourite game or SW's is lagging in performance or you want top notch performance, and hence SW or latest HW upgrade. opps you have few options to make it works.. 1) you need to master kernel programming Linux OS.. 2) ask in forum with hope someone can fix it for you... 3) 1 and 2 fail, so you pray one day someone or something will fix it for you, which can usually takes years or non at all... what you dont have is option 4... 4) it works out of the box (with HW driver or SW compatibility ready without virtualization nonsense).
this is the reason why China cheap crap HW like DSO or FG etc dont gain popularity in hobbiest market, let alone professionals. even though cheap, who have time to learn how and do programming to make it works? we want to do real work, not to make something works in order to do real work.