A NES was in my life since before I could remember. I burned untold amounts of daylight on the SNES all the way through the 1990's. Both consoles pale in comparison to what consoles are a capable of now. Yes, some games managed to be timeless, like Super Mario World and Link to the Past. But pretty much everything else is just eh by today's standards.
In other words, I prefer to not actively view the world through nostalgia goggles.
If you like PS4 games the best, that is fine. Everyone has different tastes. However, I don't think you understand that a person can still like the NES library because there are a lot of things about NES games that are objectively better than PS4 games. Modern games are not better. They are just different. Some people like PS4 games better, and some like NES games better. I don't think anyone disputes that PS4 games have far better graphics, and PS4 has a far better processor and online capability which means it can make games that the NES never could. On the other hand here are some things that NES does better than PS4, and other things are a matter of taste. Here are some reasons why a person might prefer NES games to PS4:
1. 2D gameplay - On the NES, the best games were 2D games. Super Mario 3 is arguably the best 2D platformer ever made. If a person likes 2D platformer, then the NES is the console to have.
2. Challenge - Most modern games are a lot easier than NES games. A person wanting some more difficulty would choose NES over PS4.
3. More intense action - Old games were designed with old TVs which had zero lag. A lot of modern TVs have a little lag after each button press. That means modern games have to be designed differently and this tends to make the action less intense since modern games are less demanding on reflexes.
4. Instant load times - Just put the game in and press power and you can play immediately. My PS4 takes a lot longer to turn on and I also have to do an install the first time I play it.
5. Self contained - I don't have to worry about patches and updates for an NES game. It's always good to go.
6. Simple controls - When a person is "in the zone" they aren't thinking about which button to press. They just press it. This is a lot easier to accomplish on a controller with 2 buttons and a d-pad. On the other hand it's very common to break immersion when there are 10 buttons and 3 directional inputs.
7. Local multiplayer - The PS4 library has some local multiplayer games, but that's not what it really is designed for. It's really oriented more toward online mulitiplayer. The NES has a more robust library for local multiplayer.
8. Short play times - Sometimes you just want to play for a few minutes and then do something else. The NES you can just pick up and play and put down easily a few minutes later.
9. More variety/originality - Makers of NES games were willing to take more risks, because the budgets were smaller. This is why so many classic franchises were created on the NES. By comparison, the PS4 library has very little that looks different from what came before.
The NES has a lot of features that are objectively better than the PS4. It's also true that the PS4 is objectively better in other ways. In the end it comes down to taste. There is nothing wrong with liking the PS4 best, but there are a lot of other reasons why people might like another console better. There is more going on here than just nostalgia.