Having always MBT and 40+ tanks to counter the enemy is never best answer. ATGMS can and will also be deadly against these 40+ ton tanks which are larger in size as compared to lighter tanks.
MBT is the main offensive weapon for any Ground force. MBT has protection systems against ATGM teams and there are ways to counter and neutralise enemy ATGM teams. ATGM has not made MBT obsolete. Almost every ground force in the world which can afford an MBT inducts it.
Lighter tanks are perfect for ambush and flanking enemy positions, tanks are good for front line war breaking barriers from the front. Light tanks have faster acceleration and response of turret can be exceptional using Recoil less guns on the turret for ambushing and attacking enemy light mechanized forces and buildings.
Light tanks and an MBT which is lighter in weight when compared to heavier MBT's ....are two different platforms.
Light tanks have recon and sometimes convoy escort roles where threat is not monumental. Light tank is not expected to counter MBT's but can sometimes carry a heavier cannon like 105mm. An example of light tank could be PL-01, British Scorpion, PT-76 etc. Wheeled Armoured vehicles like Stryker etc are coming up and taking the role away from Light tanks.
In weight category, PL-01 is 30 to 35 Tonnes but its called a light tank. Others are 20 Tonnes or lighter. Interestingly, T-55 MBT was 36 Tonnes when it was inducted, later up gradations made it heavier.
MBT which is lighter in weight compared to other MBT's , still retains the role of an MBT and its role cannot be replaced by a Light tank. AK is not a light tank but a lighter MBT. An MBT is used for recon only when it will be encountering threats which a Light armoured vehicle or recon vehicle or light tank cannot counter easily, but this is rare.
In Pakistan Army, its usually MBT and APC filling in two distinctly separate roles, where light 4x4 can fulfill the recon duty along with helis.
In Urban warfare sending Bradley IFV or 50 to 75mm equipped light bored cannons on wheeled/tracked armor vehicles both are more effective to fight inside city surrounded by buildings. For cold start type attack also reason is these lightly armored vehicles are cheaper and can be produced in bulk equipped with atgms to fight along side tanks is more favorable.
M2 Bradley was replaced by MRAPs as Bradley fell easily to IED's, RPG's, ambushes etc. A 25mm/30mm/40mm cannon or even a bigger cannon like 105mm can bring a wall down. Depends also if HE or AP is used. Ofcourse smaller calibre may use more rounds.
Sending an MRAP to fight in a built up area like city is probably a good idea than sending an MBT or IFV.
1.The carried personnel and crew are expected to survive the hits and ambushes,
2.its cheaper to produce and operate as its mostly wheeled,
3. it has good on road speeds where it will be operating
4. still carries a decent cannon for fire support.
5.The personnel it carries can dismount and use indirect firing weapons like mortars to engage NLOS targets.
US forces have proved that a combined task force which includes from light to medium to heavy armored vehicles is best combination than sending only single type of class.
I hope you get the point.
Its observed in recent excercises that PA also practices using this combo of MBT, APC, SP Guns, Air Defence and Gunships.
