In reality, most DAWs are not multi-thread optimized, so the difference between a dual-core i5 and a high-end i7 are pretty minimal for the large difference in prices(infact, for single or dual-threaded programs, a dual-core i5 will equal/beat the higher-end CPUs because with OC or just turbo-boost, you have higher clock performance per core due to less cooling over-head). $500-$800(assuming you build it youself) is going to get you a fast SSD, 16gb of ram, and an adequate CPU these days. "Beastly" is a matter of preference, the difference in performance between an $800 machine and a $2500 "beast" is going to be less than 20% in real-world usage.
If audio engineering is your prime source of income, then it can be very easy to justify that difference in cost, cause 20% less time can add up quickly when you're getting paid by the hour. But the OP sounds like he's just getting started, and at that level, things like outboard gear, sound cards, other equipment, gives you much more bang per $ at a low budget level. A beast computer is worthless if you don't have a good set of monitors and a good DAC.
I don't really disagree with anything you said, but I think you're over-stating how much power you really need. There's a certain threshold in terms of your career where getting those beast machines makes sense, but I don't think the OP is there yet.