With a good PC you get to play all games from the dawn of gaming to PS3+ recent releases, with either emulation and/or much cheaper prices on sales + mods + upgrades + fixes from the community. PCs are also "jailbroken/unlocked" by design.
Other than what I've already mentioned (portability/convenience), why NOT buy a PC? Price? Lack of knowledge on tampering with it?
If one isn't a casual gamer, one should definitely own a mid-high end PC before anything else.
Sure you will. 4k120 (actually UHD, not 4k) on a console, just like the base PS4 would run 4k60.
Good luck with that on titles that aren't 2D indie games. That will only happen with bad overall settings (shadow, textures, effects etc.)
And good job skipping the rest of the post, which would address some of your points.
Like I said, there are valid reasons for buying a console (Exclusives/experience/convenience) and I myself will be getting a PS5 for those very reasons, but never I'd invest on a console before getting a good PC (yours is good enough for me IMO. Hit me up if you ever wanna sell it).
As a final note, IMO, 4k is a waste of processing power, money, bandwidth (for streaming) etc. atm, unless you have a big screen TV (46"+) and sits moderately far from it. 1440p should be the plateau to aim for, for a LONG time.
I did go back and read the rest & I disagree with the majority of it. Shrug. Your comparisons are nonsense because you're saying a pc with an outdated gpu, cpu, ram, and ssd that are not even close to being up to par with EITHER the PS5 or Series X is a good enough replacement for either of them. Goalposts moved again, but by someone else this time. You absolutely can NOT build a full pc that is on par with either console even if paying msrp. You'd need at least something like a 2060 Super which is $400 alone. Now add as close to possible equivalent ram, cpu, ssd, 4k Blu-ray drive, case, fans, etc. You're spreading complete nonsense. I can almost guarantee your PC also doesn't support Dolby Vision gaming. My aging PC is "good enough"? Lmfao. You want to play most games at medium/medium-low settings in 1080p just to TRY getting a solid 60fps, and something like The Medium running at 10-20 fps with even crappy settings? Go for it. And before you go on with this nonsense that only graphically inferior indie pixel games or some shit has 120fps or that there's some huge significant changes to the graphics... here you go... and then kindly sit down.
Edit: Here's just a couple more Series X titles that support 120fps support:
Alien Isolation
Battle Chasers: Nightwar
Battlefield 1
Battlefield 4
Battlefield 5
Battlefield Hardline
Borderlands 3
Call of Duty: Black Ops Cold War
Call of Duty: Warzone
CrossCode
Descenders
Destiny 2
Devil May Cry 5 Special Edition
Dirt 4
Dirt 5
Don't Starve: Giant Edition
ExoMecha
Fortnite
Gears 5 (multiplayer)
Golf with your Friends
Halo Infinite (multiplayer)
Halo: Spartan Assault
Hollow Knight: Voidheart Edition
Hyperscape
Island Saver
Jydge
King Oddball
LEGO Marvel Superheroes
LEGO Marvel's Avengers
LEGO The Hobbit
Mad Max
Mass Effect Legendary Edition
Metro 2033 Redux
Metro: Last Light Redux
Moving Out
My Friend Pedro
Metal: Hellsinger
Minecraft Dungeons
Mirror's Edge Catalyst
Monster Boy and the Cursed Kingdom
New Super Lucky's Tale
Ori and the Will of the Wisps
Orphan of the Machine
Overcooked 2!
Overwatch
Paladins
Plants vs Zombies: Battle for Neighborville
Plants vs Zombies: Garden Warfare
Plants vs Zombies: Garden Warfare 2
Power Rangers: Battle for the Grid
Rainbow Six Siege
Realm Royale
Rocket League
Rogue Company
Samurai Shodown
Sea of Thieves
Second Extinction
Star Wars Battlefront
Star Wars Battlefront 2
Star Wars: Squadrons
SMITE
Superhot
Superhot: Mind Control Delete
Super Lucky's Tale
The Gardens Between
The Falconeer
The LEGO Movie Videogame
The Touryst
Titanfall
Titanfall 2
Tony Hawk's Pro Skater 1 + 2
Totally Reliable Delivery Service
Unravel 2
Unruly Heroes
Untitled Goose Game
WRC 9
Zombie Army 4