it's the opposite; having a PS4K, I can't find more reasons to build an expensive PC, when PS4K will show roughly the same quality in multiplatform games, and better visual with Exclusive Games.

Consoles are always the better choice for the majority of Casual and Casual-hardcore gamers. Gaming on expensive PC is niche.

Unless there's some form of magical chipset with fairy dust or the price is several thousand dollars, I don't think that PS4 exclusives will look better on a PS4K than on a high-end PC. Console games usually have visual settings on par with medium-low settings on PC, which are easily run by most somewhat modern rigs at decent frame rates. The fact that consoles are, to this day, largely limited to 720p, 900p or 1080p and only 30 fps speaks volumes of the difference. My old gaming rig, which is nearing on six years old, plays new games in 1080p just fine and over 30 fps at that.

Also; consoles are not always the better choice by default, I still have no 8th gen consoles and only bought about 15-20 console games during the entire 7th gen, and I consider myself as someone who spends a lot more time and money on gaming than average. If you want minimal fuzz and have little to no technical knowledge (and lack the desire to gain it) and like games in genres usually found on consoles then consoles are probably your best choice, sure enough. I'm a bit confused what you mean by casual-hardcore though, seems like a self-contradictory label to put on something or someone.
Gaming on expensive PC is somewhat niche, hard to argue with that, but high-end rigs aren't the only ones capable of playing modern games. As far flexibility, software prices, free online, games library, customization and multi-tasking go, the PC is still unbeatable as a platform.

PC gaming has always been more enticing, however, the convenience of console gaming will always keep itself popular.