iPhone 7 Plus screen scratches

You're not writing Apple. This is a user to user only forum and Apple will not respond to you. You can schedule an appointment at your Apple Store Genius Bar and show them the phone. I would not expect a replacement however. You're probably not seeing actual scratches in the screen itself. Your phone is coated with a scratch resistant (not scratch proof) coating. If you keep the phone in your purse for example and keys come in contact with the screen, it could make micro-scratches appear. If I were you, I'd put a good quality screen protector on your phone and the micro-scratches you see will most likely not be visible.

BTW, your Rolex analogy doesn't work. Rolex crystals are Sapphire. They can easily shatter, which is why no phone currently on the market has a Sapphire screen. And yes, I put a screen protector on every iPhone I've ever had because in addition to helping the screen stay pristine, it also can help absorb shock if you ever drop your phone. I've shattered screen protectors, but never shattered my screen.

A new Rolex would have a synthetic sapphire crystal, but so do many cheaper watches. Won't scratch (except from a diamond or sapphire/ruby) but can shatter pretty dramatically.

But the iPhone screen is made of glass. It's very hard considering it's glass, but it's not scratch proof - especially if you're in an area with a lot of loose sand. It's certainly not marketed as being scratch proof.