$2-4k/yr assumption is flawed. Most of the land in india only has one crop due to shortage of water. It is totally dependent on weather which is increasingly becoming unpredictable and requires investment in seeds and fertilizers. In short its not even profitable. Migrant workers from rural areas in east(UP/Bihar) frequently go to work as agricultural laborers where 3 crops can be grown like punjab/haryana. So manufacturing even low value goods would be net positive.

How does RR explains rural and urban unemployment if he thinks wages are high enough? RR is excellent economist and his arguments might be valid considering the data but the data itself doesn't reflect the ground reality so conclusions are flawed as well.