I think the Key point would be, could you hear any difference in those test?

If you could, then yes there is a quality differential, rather you got it right or wrong may be subject to taste. But at least we established there are differences.

But when we say 128Kbps are sort of CD Quality or CD being no-difference to 320Kbps mp3, they generally refers to vast majority of consumers, not audio experts. I think most consumers could tell the difference between 256kbps AAC and 128Kbps MP3. But beyond that it sort of goes into consumer dont give a damn territory. Although most Pros would want the highest quality possible and there are no reason why we cant deliver lossless with today's infrastructure.

I am wondering if there is a market for an even cheaper Music Streaming Services that target lower quality, 128Kbps music.