It seems it isn’t really that costly to build a nice 1000 sq. ft. place complete with appliances and modern amenities.
The construction industry in India is shitty - carpenters, painters, plumbers, masons, general contractors have little to no professional training and eff up projects often, the tools aren’t modern and renovation work is infrequent because of the poor quality of construction services (and non-existent DIY culture and ecosystem). Also, it’s probably looked down upon in the Indian society if a house owner goes DIY with any construction work (gardening is an exception).