Question about texture resolution & game size & industry standard texture sets

First question: If I have 3 textures for a single asset (diffuse,masks,normal) that are each 2k resolution, the engine image editor tells me that each texture size is 2.7MB except the normal, which is 5.4MB, totalling 10.8MB. Does this mean that if I have 200 assets using the same texturing method, that my built game would have ~2.2GB in textures?

Second: I noticed some AAA games such as fallout 4 have dozens if gigs worth of textures. Does each of their textures have their own “set”, hence the huge amount of HDD space taken up by textures?

Third: If I reduce the texture size under compression->compression quality in the texture editor, does that translate into a built game being smaller in size?

here is a simple explanation (not professional) :)))

if you only have a 10MB texture and 200 simple static meshes which are using the same texture then your whole content size will be something like 10.50MB.

if you compress it, your package size will be much smaller but there will be some extra work for CPU to decompress it.

if you have a huge open world map made by those 200 meshes with the same texture, your content size will be still the same (10.50MB).

when you import a 1k texture to engine, engine generates its 512,256,128,64,… as mipmap later it can use it.

now I have a 10MB size content consisting a texture and some meshes. my package size maybe 100MB including engine’s contents, codes and… when i run my game CPU will have to load my 10MB content to RAM but in my VRAM there maybe more than one copy of that texture but engine streams those copies of texture which are in a distance from camera using already generated mipmaps.