When i was younger, I primarily owned consoles since NES days due to lower price of hardware, co-op/multi-player with friends in the same room, exclusives.
1) Lower price of hardware is irrelevant now. I need a PC for work/productivity/continuing education, which means might as well pay a little more for a gaming laptop or if you built a desktop, it's cheap to get a 1080p graphics card upgrade. $200 RX 480 gets you better than PS4 Pro's iQ/performance, $350 GTX1070 get some you 1440p.
The huge discounts of PC games on Steam, GOG, GreenManGaming, CD Keys, Origin, UPlay and various humble bundles ensure that the savings on software easily offset the cost of a more expensive CPU/GPU like the 6700K and GTX1070. Due to cryptocurrency mining on the PC, I haven't paid for a graphics card since 2009. Every graphics card I've owned since HD4890 to R9 295X2 and GTX1070 SLI has been completely financed with Bitcoin, Euthereum and ZEC. Next year I will get a free GTX1080Ti or Vega 10 cross-fire after reselling my existing cards and selling virtual currency.
CPUs such as 6700K/6800K now last 5+ years without needing to upgrade. $60 a year x 5 years PSN or XB Live = I buy a new $300 CPU again from money I didn't waste on online on consoles. Hard drives, power supply, case, BluRay drive can all be reused. Good power supplies from EVGA, Corsair or SeaSonic have 10-year warranties.
The PC hardware itself opens a new world of possibilities. With the PC, I can use Xbox 360 or DS4 controller or K&M. I can game at 1080p or 3440x1440 or 4K or use a 4K HDTV with HDR if I wanted to. A lot of console defenders here talk about Bloodborne but won't discuss how the game stutters and drops to 20-25 fps. Soon we will get 240Hz 1080p, 200Hz 1440p, 120Hz 4K PC monitors.
2) Co-op and same room multi-player on modern consoles is more or less dead. Compared to the glorious days of NES, SNES/Genesis, N64/PS1, GameCube and PS2/XB1, Xbox 360, the nearly complete shift to online gaming has managed to destroy the LAN aspect of gaming with 3-4 friends multi-player. This unique console multi-player experience has been largely replaced by playing online with friends. It's just not the same.
3) Exclusives. Wii U exclusives were too few. XB1 exclusives are a complete joke since Forza Horizon 3, Gears of War Ultimate, Gears of War 4, Quantum Break and more to come are all better on the PC - better graphics, more control options, better frame rates. Except for 4K BluRay and sports games, XBox eco-system offers nothing for PC gamers.
That brings us to PS4 and the Switch. 99.99% of all cross-platform games are better on the PC. 3 years after PS4 came out, I got the Slim U4 bundle for almost 1/2 price of the OG PS4 and it's now possible to pick up LOUS, Bloodborne, Killzone Shadow Fall, Uncharted 4 The Collection, Ratchet & Clank, God of War III remastered, Until Dawn, Infamous Second Son for $10-20. That's an extremely small list of worthwhile games on a ~ $200 console after 3 years on the market. If I paid $400 for launch PS4 and $50-60 for these games at launch, I would feel like it's a big waste of money. 3 years is almost the entire life-cycle of the Genesis and N64. PS4 exclusives are taking forever to come out.
Personally, I think console gamers will only realize how much less consoles have to offer if they were given a library of 500 Steam games and a PC with 6700K, GTX1070 and a 144Hz 1440p GSync monitor. It is very easy to accumulate that from 2005 when the 360 launched. If you have that, besides sports games, and PS4 exclusives (right now it's not that many titles), the PS4/XB1 is one of the LEAST impressive console generations up to this point. In fact, God of War III, Uncharted the collection and LOUS aren't even PS4 exclusives.
Overall, the consoles are losing their unique appeal to PCs. PC gaming is becoming more versatile, cheaper, and the PC gaming library is growing because the games are backwards compatible for 3 decades at least. There are already more gamers on Steam than the install base of PS4+XB1+Wii U combined. Over the next 10 years, PC gaming will grow MUCH faster than console gaming. Sooner or later the 18-25 year olds on here will get good jobs and have $ for a 6-8 core i7/Ryzen and a $500 graphics card. I used to be a pretty serious console gamer only but once I got a nice PC, I now only use consoles for exclusives and sports games.
The #1 reason most people on here don't have a high-end gaming PC is money. It has little to do with PC exclusives or K&M excuses. The choice of owning a console and not a console + a PC is 99% because most of you are probably too young to easily afford both. Once you can easily afford both, it makes absolutely no sense to not own both consoles and PCs to enjoy the benefits of each eco-system.