Hi Tom (@tomkeet)
Apart from my aging laptop all my machines are home builds and have been since a very long time ago. However, a pre built machine may well be the only way to get a good deal on the graphics card because they frequently lower their margin on the most expensive element (currently the graphics card) to keep the cost competitive.
Typically I port a build from one machine to another (clone the SSD) and then sort the licensing issue out for those that check the machines finger print every time (like PL5). The porting is not to fool the licensing but rather to ensure continuity, it has taken a long time to get my machines the way they are and it would take a huge amount of time to rebuild the software environment from scratch.
Some of my history is included in PL5 - DeepPrime and performance gain on Windows? - #22 by BHAYT. I can understand looking for a more straightforward route but I don’t find putting the hardware together anything like as complicated as trying to make an old build sit comfortably on new hardware!? I would still have that problem if I purchased a ready built system!