The monitor that I will be using for this GPU is 1080p and 60 Hz, and so I know it's more than enough and won't be a bottleneck.That's completely incorrect, if you're using it for gaming, you would have to upgrade the GPU, as already it will be a bottleneck immediately as it's very underpowered for most modern screens.
That would last maybe 2 years before you're not managing 60fps which is considered the absolute minimum to be classed a gaming PC.
Any gaming PC, the first bottleneck is the GPU, and any gaming PC needs a GPU upgrade first of all.
I don't understand what you're exactly saying is going to happen from now to 2 years later where my PC is going to drop to under 60 FPS. If it can perform upto what I need for it now, there isn't gonna be a massive change where it's all of a sudden going to drop.