I certainly can't speak for every open world game out there, but from my experience, the PS4 is perfectly capable. In any case, Zero Dawn is still concrete evidence of what the base PS4 can do.
I realise that people will have wildly different experiences with PC gaming, so what I'm about to say will not necessarily have been your reality. That said, PC gaming hardly sets a good standard for well functioning games. Have a AMD GPU? There's a good chance the latest game outright won't work on your system. Bought a new GPU/CPU? There's a good chance your older games now require work to be able to play on your system, or won't work at all. This on a PC that is touted as being backwards compatible... And beware that you'll need to replace the GPU after two years if you want to continue maxing out the games, and that is assuming that the card you bought was a top of the line model, sometimes costing more than consoles do at release. I've done my fair share of PC gaming. I still do it a little because I happen to like RTS games and a few FPS games, the former of which is mostly nonexistent on console, and the latter arguably playing better with a mouse. But for anything else, I go for my console, because it saves me the annoyance of the game either requiring work to function correctly, or the game not working at all. Both of which are problems I have experienced a lot on PC, despite it being a rather expensive setup. Problems that, when combined with excessive DRM BS, game clients (Origin, UPlay) and mods shifting from free to being paid, have caused me to tire of the whole PC model.
PC gaming undeniably offers better performance, but most of it is theoretical rather than practical, and it comes at a higher price. That the base PS4 is capable of powering the best looking games (in terms of photo realism) currently out there is not an opinion. It's fact based on what has actually released on the system. That doesn't change the fact that you could achieve even more on a beefy PC, but what does this matter, when the lack of optimization due to the ridicules number of different setups prevents this from happening? As much as I like Crysis, to give an example, I hated not being able to play it on high settings for many years until after it originally released.
A lot of people like getting really into their hardware, and they have the money to spare. That's all well and good. That's what PC gaming, I think, is about at its core. Console gaming might not be that hardcore, but they work, as do the games. Neither should change to accommodate the other, as doing so would mean alinating either PC or console gamers.
