Iphone 14 Pro Max main camera photo saved at 12MP resolution not 48MP

iPhone 14 camera, is 48mp, but when you take a photo using standard processing it uses a Quad Pixel sensor format, meaning your photo will store as 12mp. If you truly want to take photos in 48mp, you need to use Pro Raw, which will actually take pictures in that huge size. If you do that often however, I hope you purchased a LOT of memory as 48mp photo's will eat up memory very quickly.

Here is information about Pro Raw --> About Apple ProRAW - Apple Support

Because that's how Apple designed it. Quad Pixel design in standard photos to store at 12mp or full 48mp in Pro Raw. And your analogy doesn't work. If JPEG's stored at 48mp, it would take up just as much space whether JPEG or Raw. You, the photographer have the option to choose how you want to take photos and how large they should be. No one is limiting you here at all.