So u suggest we keep being their hostage? Suffering from Stockholm syndrome are we? Yes we used F16 and we could have used others too, but we have a huge fleet of it and huge cache of weapoms, better use them before they expire and we dnt get any new. Also dont forget the US wanted our help in Afghanistan and hence the reason why they didn't give us grief. If we were not required, they would have sanctioned us to please india.
Chinese on the other hand have never even threatened us, u need to understand their culture to know them well. They have no intention of enslaving anyone and the past clearly tells us we can trust them more than the US.
Also Pakistan is no kid, we will always keep a certain level of diversity in our weapons and capabilities, distributing our reliance and not fully relying on one nation e.g we prefer Turks in many aspects.