Why is Yash Raj Films not enthusiastic about making 'Tiger 4'?

Why doesn't Yash Raj Films want to start work on 'Tiger 4'?

Nowadays the discussion is going on that Salman Khan has decided not to work in Yash Raj Films (YRF) spy universe's upcoming films 'War 2' and 'Pathan 2' ('Have decided', decided not taken it,