By “shuttle” you mean bus? If so Tsuen Wan is not so close. Tuen Mun is closer. I took a shuttle bus from Tuen Mun to Guangzhou three months back and it was pretty fast. But with the new high speed rail nothing will beat that.
I think you have it backward. It’s always better if you have more money than locals. You can hire an army of servants to take care of you. If you wait until the whole country’s living standard catches up why bother moving? It will be the same as here.
Growing up, I was told not to go north of Mong Kok, and I think I’ve only been to Sham Shui Po couple of times to buy pirated software
So yes, I missed the boat on Shen Zhen big time. Back then, Sha Tin was also considered “up & coming” but we laughed it up as boonies. I’d imagine Sha Tin has finally “come” now?