PC
- Free online
- Cheaper Games
- Settings options in games
- Mods
- Controller or mouse and keyboard options
- Emulators
- Old game compatibility
- Steam
- More games
- Better frame rates
- Better visuals
- Pretty much everything

Consoles
- Better exclusives

Nintendo + PC = happiness

It's all about the games. Mostly about the AAA exclusives for that matter. Here's 2014-2016 to be specific.

PC
WoW: Warlords of Draenor
Pillars of Eternity
Homeworld Remastered
Cities: Skylines
Heroes of the Storm
Total War: Warhammer

PS4
Uncharted 4
Bloodborne
Odin Sphere: Leifthraser
Ratchet and Clank
Disgaea 5

3DS
Bravely Default
Theatrythm Final Fantasy Curtian Call
Persona Q
Poke'Mon Saphire/Ruby
Majora's Mask
Monster Hunter 4 Ultimate
Devil Survivor 2: Record Breaker
Etrian Odyssey II
Fire Emblem Fates
Monster Hunter Generations
Bravely Second: End Layer

XB1

Forza 6
Rare Replay
Halo 5
Forza Horizon

Wii U

I just can't imagine missing out on these games. Just a single console, or just a PC doesn't cut it, not for me anyway. 

consoles:

You can play local with others

you can play on a couch

So damn true.

Traditionally consoles are high convenience, low flexibility, whereas PCs are low convenience, high flexibility.

On console, there is one, and only one way to play this or that game. And if you can't make it onto the official store front, or get a full boxed publication, then your game can't get onto consoles.
But because the hardware, and software, and distribution methods are all standardised, you can trust that all you have to do it put the game in the machine, like any other game into any other machine (because they all work the same way!) and you can just sit back and get playing. And since developers know that all consoles of the same line will be identical, they only have to develop for a few sets of specs.

On PC, you have to put some work in. Do you have sufficient hardware to run this or that game? Will it conflict with your software? If it does, do you have the technical know-how to fix the problem?
You wanna bump up the settings? Do you even know what half of those settings mean, or if your rig can handle them?
But it's an open platform, which means you can go to get games from anywhere. If a game can't get onto one of the big storefronts, you can just download it directly from the maker's site. If it's a file, and you can get your hands on it, you can play it. But nobody checked to make sure it works, or that it isn't loaded with viruses or something. So you have you have to take responsibility.
There are so many different configurations and performance capabilities, so PC development can get dicey.

But this comparison is starting to erode. PCs are becoming a bit more like consoles and consoles are becoming a bit more like PCs.
We'll soon have different versions of the same consoles with different hardware. We've very occasionally seen graphics and performance settings popping up in console games. It feels sometimes like you need to sit and download an update every single fucking time you want to play something. So the convenience of consoles is starting to drop while how you play is becoming a bit more flexible.

Meanwhile PCs... well... Windows 10, basically. Windows 10 is happening. Microsoft's long term goal may be to monopolise software distribution, and their new UWP format is locked down and un-alterable. You play it how they envisioned, or you don't play at all - the antithesis of the flexible appeal of PC gaming. Did a dev release a buggy game? Do they have no intention of fixing it? No problem, Durente or someone else will come along and fix it just for kicks. Oh no... it's a UWP. Now the devs won't fix it, and they won't let you try either.

So the gap between consoles and PCs is narrowing. Is that a good or a bad thing? Only time will tell.
Will the new variety in console specs prove too much headache for developers and will buggy, poorly optimised games become a common occurrence on console?

Will PC become an inflexible platform where you won't be able to do anything with your games that devs/publishers didn't specifically intend? Basically, will the open PC platform get a lot less 'open'?

It all comes down to what exactly a PC is. Now days a PC can be your phone, you computer, you console, your TV, etc.

And some companies might be a little over-zealous about trying to bring all these platforms together to the point where their effectiveness at their individual tasks is negatively impacted. That's what happened with Windows 8. Rather than one OS that was great on smart devices and another that was great on desktop computers, we instead got a single OS stretched over both that was okay on smart devices and ghastly on desktop computers.

Thanks. I missed that. Updated the list. 

Me too, not sure why people thinks otherwise.

I agree with your points and I add one to PC, in most cases, if you aren't a total power enthusiast PC user you can keep you PC for many years and you'll just need partial HW upgrades to extend its life making it able to run new games at medium-high settings. Obviously, the highest settings you want, the sooner you'll need a total upgrade, but luckily it's not mandatory for compatibility.
About consoles, you wrote in another post you put physical support low in the plus list as it requires some more efforts, making it closer to PC experience, but physical on console is usually smoother to install than on PC anyway, as on each console there is just one (or at most very few) standard HW and SW config.

Just don't let me know what else you use your PC on the couch for please!