Cost of power windows, electric OVRM and other small accessories is not enough to equal airbag's cost , which is around $400 for driver and $1000 for passengers (along with related mechanical sensor - not electrical accelerator based sensor). There are lot of misconception about NCAP:
First off, NCAP has not taken Indian traffic into consideration. Mixed vehicle traffic, lower engine power, lower average speed in general traffic , different deaccelaration pattern all affect the frontal overlap and crash speed.
Second, a 1 star NCAP rating equals 40% probability of injury in a collision between similar vehicles. Altered accident dynamics – like collision with heavier body vehicle - which is arguably more common in Indian mixed traffic, lane less roads- nudges the probability towards 50% - which of course, means statistically, the 1 star NCAP is of no use. You can get a 1 star rating by adding 2 airbags (assuming present structural strength – except Datsun) which pushes the cost of cars by 15%. The price elasticity of entry level hatchback is only Rs.5,000. Why should the manufacturers lose highest selling segment over a dubious rating ? In fact adding the airbags in India where the co-passenger never ever belts up is going to cause lot of injuries due to mechanical airbag sensors (which needs to predict collision and deploy before hand to offset mechanical delay). Don’t imagine a lower trim car will ever get an electrical accelerometer based sensor.
If you really want a safe car, you would need a 4 or 5 star NCAP car were injury probability is equivalent to 5%. However the safety features would equal or exceed hatchback’s total cost. No one is stopping those who want safety to go for a higher priced variant.
If the Government wants safety in lower variants, let them reduce taxes and RTO charges drastically. Those advocating NCAP are unwittingly practicing economic untouchability. A middle income family has as much right to get a 4 wheeler as any other income group. By falling into trap of NCAP (especially 1 to 2 star rating of car), they are putting 4 Wheeler out of reach of average income family.
Lastly, NCAP has nothing to do directly with ABS and other safety features.