Yes, but considering the expected lifespan of a CPU at stock clocks is >10 years that shouldn't be a problem. Also apart from really high voltages that just kill it instantly the main effect is degradation, needing more voltage for the same clockrate. Which of course can be easily fixed by either lowering the overclock once it gets unstable after a few years or by upping the voltage a bit (which will speed the process up marginally).
Mobo and RAM are actually ok-ish (could be better, RAM probably not the best timings, but neither actually bad).
PSU is cheap low end 80+ (not even 80+ Bronze, just 80+). All assuming that steam profile you found is actually that pre-built, but the case doesn't match.
I'd actually argue that they cut corners on the CPU and GPU too. Lowest clocked i5 isn't really what you want for games since you're paying almost the same as for a faster i5, but depending on the game it might actually be slower than a much cheaper i3. And you really don't think the fact that the MSI Armor 4GB is the cheapest RX 580 is a coincidence? Especially with 4GB a higher clocked RX 570 would be more or less the same speed but significantly cheaper. Not so much cutting corners to get the same performance at the cost of lower quality, but to get the impression of higher performance at the lowest cost. RX 580 > RX 570 and i5 > i3 seems obvious, right?
Depending on how much you pay for windows it would cost more or less the same, with more work for you if you build it yourself. So you're definitely not getting ripped off.
The second problem of pre-builts however is do you really want/need those parts? If you want a better mouse and a mechanical keyboard then those included are of essentially no value to you.
Anyway there's multiple options:
1. The pre-built. Would just about do what you want. Maybe add an SSD. Replacing the PSU would add cost so building with the same specs should be cheaper.
2. Building with minor improvements (SSD + maybe different CPU/GPU).
3. Building with major improvements. Do you need a new monitor if you stick with 60Hz for now? Do you need SSD+HDD or can you get away with just an SSD?
Also can you get windows via school/college/university?
PCPartPicker part list / Price breakdown by merchant
CPU: Intel - Core i5-7600 3.5GHz Quad-Core Processor ($218.77 @ OutletPC)
Motherboard: ASRock - B250M Pro4 Micro ATX LGA1151 Motherboard ($52.98 @ Newegg)
Memory: ADATA - XPG GAMMIX D10 16GB (2 x 8GB) DDR4-2666 Memory ($145.99 @ Newegg)
Storage: Samsung - 850 EVO-Series 250GB 2.5" Solid State Drive ($84.99 @ Newegg)
Storage: Seagate - BarraCuda 1TB 3.5" 7200RPM Internal Hard Drive ($49.56 @ OutletPC)
Video Card: MSI - GeForce GTX 1070 Ti 8GB Titanium Video Card ($459.99 @ Newegg)
Case: Cooler Master - N200 MicroATX Mini Tower Case ($34.98 @ Newegg)
Power Supply: Corsair - CXM (2015) 450W 80+ Bronze Certified Semi-Modular ATX Power Supply ($48.99 @ Amazon)
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-12-08 07:40 EST-0500
Get any case you want.
If you insist on getting an aftermarket CPU cooler you can go for an i3-8350K + Z370 mobo. Due to only Z370 supporting it, it'll be slightly more expensive (albeit slightly faster as well) even though the 8350K is cheaper. The main difference is that 8350K doesn't come with a cooler so the end result would be significantly more expensive, but if you're buying one anyway then you might as well take that little bit of extra performance and the option of overclocking. Usually K CPU + Z mobo when you're not overclocking isn't worth it, but in this case if you buy a cooler anyway it's only a 10$ difference with a minor performance improvement, so definitely worth considering if only for the resale value.