AK series is not outdated, the adversaries that it faces are not just "outdated" indian armor fleet, but threats from ground and air like ATGM, artillery, mortars, hand held RPGs, IEDs, mines etc. Indian armor doesnt set the standard for Pakistan Army, however Indian armor threat has to be countered, and not just through tank vs tank. Now in the air, its a fighter aircraft vs fighter aircraft, and then a SAM threat. On the ground, its very different if you see the threats i mentioned. A fighter aircraft in the air has to be downed to neutralise it, whereas a tank can be made immobile or unable to be recovered by enemy, while its still intact. JF-17 as well as AZ and AK series were made to stay afloat with economic condition of Pakistan. Its not like Pakistan is on a LEO2/M1A2 buying spree. 3 decades is a long time, technology is coming up fast and is being incorporated in current weapon systems of Pakistan.
Drones have their own limitations. Range, endurance, payload, threats, comm links etc. Tanks have their role, a role which no other weapon system can fulfill till now. A combination of weapon systems in combined arms Ops can come on top at the end of the day.