Incorrect. I have a gaming PC that is over 5 years old. Granted I have upgraded the video card over time, but from a CPU and memory standpoint, it is the same.
What you do is you slowly buy your machine piece by piece from newegg. Prioritize the first purchases to be the items that age the best. CPU, motherboard, memory, power supply, case and hard drive (SSD). Finally get the one thing that ages the fastest, the video card. It may take you over a year to put it together, but you can do it. When you are done, you should have a good machine that only needs a video card update once in a while. As soon as the machine is built, start saving right away for the next upgrade.