Long term benefits to skin care routines???!!!

I once heard a doctor say that people forget that the skin is nourished from the inside out, and that therefore there is no need for constant obsession with putting creams on the skin. It seems very convincing to me, and suits my basic understanding of there being a dead layer of skin cells on the surface of the skin. Even if certain nutrients could penetrate beneath this layer, then what's the point of it if you would be getting such nutrients in your diet anyway? It was Dr Mark Hyman who said it!

But in spite of this, every time I hear someone speculate as to why someone (usually a celeb) has aged so well, it's one of two things they always mention first; a good skin care routine, or plastic surgery. They don't tend to mention diet, exercise, or adequate sleep as being the reason(s). Strange! Of course it suits the economy for people to think like this. But even if a good skin care routine does actually have benefits, it's surely trivial compared to the 'long term' benefits of any one of these three other things? I'm also under the impression that the skin care measures that do have a benefit are usually only short term benefits anyway. It seems like there's so much marketing and peer pressure for women to do these things, that even the educated ones just sort forget that there's actually no need to.

When it comes to a skin care routine, apart from using sun screen and face washing, I don't know anything about what one should actually do! I'm also assuming that if tried to learn about what creams I should/shouldn't be using as moisturisers or anti-agers, that I would quickly become confused.

But I do have to acknowledge that well regarded qualified people do seem to constantly refer to the importance of a good skin care routine in order to stay healthy looking! For example I've noticed the plastic surgeon youtuber Gary Linkov refers to it a lot. He speculates that celebs like Megan Markle and Tom Cruise have skin care routines. So is my understanding in all of this wrong? Is there something I'm missing here?

I don't even bother to wash my face!