>>365457646
Your dunning kruger is strong! That's okay, you'll get better over time as you learn more. 

>Most modern shaders these days can "guess" the light direction from the ambient lighting, and this looks and works really well.

Okay, that's nice, but there's lots of things that need the UNITY DEPTH BUFFER. The depth buffer is NOT activated without a directional light. You USED to be able to do it with post processing. This does not work in vr with 2019.4.31f1 Set it to "Not important" if you want so it's a vertex light, however unity ALWAYS renders a single directional light (but doesn't enable the depth buffer!) so it's basically free. No reason not to do it. 

>14 textures isn't necessarily all that much in a large and well-lightmapped world.

No. just.. no. It's horrible. It breaks batching like mad. If a single light is casting a shadowmap across two static batched gameobjects using the same material and the lightmap is broken you're now rendering four of them. Please learn how to use and read the frame debugger before you shoot your mouth off. 

>this is useless for anything except download size. textures live in VRAM non-crunched, even if crunched beforehand.

LMAO. 

A crunched image decompresses directly into DXT1 or DXT5 with no additional steps, and decompresses EXTREMELY quickly on the gpu. The idea is a crunched texture can be read from the disk and decompressed into a DXT5 faster than reading a DXT5 straight. 

Skinned mesh renderers are the only textures that live in VRAM and your ram. 

Finally:
>"baked flat ambient color everywhere". 

No, I didn't say that. Ambient light is for dynamics in the scene, like avatars and pickups. I'm suggesting you bake the LIGHTMAP into the ambient.
It's not good for every use case, it's just a really nice way to get a huge amount of performance if you're not a blender brainlet.
I didn't say "don't use normal maps or pbr". I said bake the static shadows into the albedo. Christ, please learn unity.