Treatment as in what? The media portrays these individuals as victims, when in fact they blossomed under TVB. If the criteria ain't fitting, these 'artists' are free to leave. It's very very obvious that talent, looks, charisma, etc. etc. are very easily replaced. What exactly are you trying to say? That that these artists are doing it for passion and not money? I don't get it.
The provision of many of the contracts that TVB enforces on their players, prohibition on working outside of their farm, and work only at the pleasure of TVB. They're allowed to blossom, but only if TVB wants them to. There is really no artistic independence because frankly, HK media was essentially a closed and tightly controlled market. But, ever since the return of HK to China, things have changed. There are a lot more media venues that can be taken by established stars. This is one of the major reasons why TVB had to resort to its stable of Keh Leh Fehs. They were the only real actors that TVB could rely on after defection by established players. But by sticking to its long established closed fist ways of doing business, even the KLF's now are finding greener pastures. So, like you stated, they're free to leave, and they're doing so.