Before induction of FM-90 & LY-80, Pak Army Air Defence relied on MANPADS & guns only. FM-90 is the first system that Pak Army got which gave them air defence capability in the beyond visual range area otherwise it was MANPADS only for them.
It was the Air Force which had in service with them the French Crotale SAM systems before anyone else and then the Aspide 2000 / Spada system.
Since PAF owns the majority of the air defence radars and has a command and control since many decades, i believe its their responsibility to have the Medium & Hi altitude SAM systems. Army should concentrate on point defence systems to protect its forward HQs & armor formations, and leave rest of the country to PAF.
Its wastage of resources, but if these systems are to be used for the protection of strategic assets then may be. But then again with long range precision weaponry coming into play and cruise missiles, effectiveness of such systems remain a question.