There has been no major war recently to show that AEWACS is perishable. But, in war one must always expect the worst. 4-5 escorts are no big deal. The AEWACS are big fat planes and can be taken out by ground based SAM or BVR. The escorts really have no way of defending against incoming missiles. Since the planes have massive RCS, they will be easily detected from far away and targeting will also be much easier.
Moreover, importing is never an option in war. It is like expecting other countries to fight our war. If we fight, it will be with our equipment.
The mini AEWACS are actually much more useful during initial stages of war where air superiority hasn't been achieved yet. They are cheap and are expendables.
SARAS can also be extended into a bigger plane by altering the design. The design for simple planes like SARAS is not hard. The FBW etc are pretty straightforward. These are planes with high aerodynamic stability. So, once a smaller SARAS is made, it will eventually extend to a larger one with tens of tonne payload for military transport and bigger AEWACS.
See AWACS is not something which is still considered perishable even in the present scenario. An AWACS cover any battle from standoff distances still gets escorted by 4-5 high-performance fighter jets at all time. That is why these are considered HVT by adversaries........................As for smaller ones called AEW, well you can mount smaller AEW system on stretched SARAS or even on present SARAS and use it like SAAB 340 operates.