I've never said anything about hard disk space being used. I could care less how large files are. As long as they work in a game.
I have indeed used many texture files of my own making and in different maps retained the same name for those textures - but - even though they have the same name, they are different in many aspects according to which map they were used in. So, anyone wanting to use one texture of the same name in different maps, is going to get very odd looking maps.
And besides, with each map having their own specific texture folder, it makes things much easier when installing and deleting maps.
I do believe however that in years past it was agreed that enlarging a 512x512 texture into a 1024x1024 just by multiplying by 200% didn't really add anything extra to the texture, detail-wise ... so, by analogy wouldn't the same apply to turning 1024 textures into 2048 textures?
Which is why I would think that only by making new, fresh 2048 textures, would the difference be visible in game ... so I'd really love to see a newly made 2048x2048 texture map.