In the 1970s, cost. The PAF liked the Mirage F-1 and Mirage 50, but it wasn't affordable enough to support a workhorse requirement. In the 1970s, the Mirage III/5 were basically the PAF's top-tier fighters. They maxed out at around 96 new-built aircraft.
It's worth remembering that the PAF originally ordered the Mirage III when Pakistan was a 2nd world country. We had both West Pakistan and East Pakistan. We had an economy that wasn't skewered by PPP nationalization nonsense. In other words, our defense budget was much,
much more pre-1971.
Just to put it into perspective: in 1966-1970, we ordered 26 Mirage IIIs, 28 Mirage 5PAs, 60 (?) F-6s, and 3 Daphne SSKs. We were also talking with the Soviets about the MiG-21 and to Sweden for the Saab 105 (with production license). We literally ordered more than 50% of our new-build Mirages pre-1971.
@JamD @kursed If not for 1971 and the PPP, the PAF would've probably had Mirage F-1s. Heck, Pakistan might have been building them in Sindh while launching ships and subs from Bengal.
In the 1980s, the PAF considered the Mirage F-1 as a possible successor to the F-6. In response to the Sabre II program, Dassault offered to transfer the Mirage F-1 manufacturing line to Pakistan plus a large stockpile of Atar09K-50 engines. However, the PAF dropped Sabre II and decided to focus on buying F-16s as the workhorse fighter. In the 1980s the F-16 was coming at a markedly affordable pricepoint. With Peace Gate III/IV the PAF would've had 110 F-16A/Bs, and then ACM Qureishi said in the 1990s we had an option for another 50. So by 2000, the PAF was probably aiming for 150 F-16s plus the 96 Mirage III/5 (ROSE-ed probably).
