Why was Robert Patrick never recruited again after Terminator 2?

It seems he didn't want to unless it was with James Cameron...

In the past, Robert Patrick has been everything from against, to luke-warm towards, reprising the iconic role that made him famous. But now things have changed. This is apparently due to the return of James Cameron to the Terminator franchise.

This is what Robert Patrick had to say about it to Yahoo, in regards to playing the T-1000 again:

ROBERT PATRICK: “I would. I thought about this. I’ve been sort of… it’s changed my position over the years but yes, I would, I certainly would. Especially now that Jim Cameron has the franchise back in his hands. The common denominator I think between Terminator and Terminator 2 is the fact that Jim Cameron directed both of those films. If he’s involved, I would love to be involved again. I honestly can’t say I can do it quite as well as I did it as a 30 year old physically, but I sure would give it my best effort.

^Source

James Cameron will acquire the rights back in 2019, as copyright reversion takes place after 35 years. More at Wikipedia