Why are the manufacturing jobs moving from China to Vietnam, or Thailand, or Cambodia but not to India?

Proximity to China.

The amount of white collar jobs practically shot right past any blue collar opportunities in India for a good life. The perception of people doing different kinds of work influences choices and opportunities.

Because India isn't ready! Indian govt doesn't know how to cash an opportunity, with the trade war with China it was a perfect time to step in and get the business but the government couldn't care less. There is no incentive for the businessman there, example in Hina the govt encourages the factory owners to produce surplus as mass production is cheaper with a guarantee to buy what isn't sold in India there isn't any such incentive. It is extremely hard to start a new business in India because of red tape. One notable busineesmanTata, wanted to get into airlines and he got so frustrated that he said "I am an Indian and yet I find it so hard to start a business, being a career businessman, I wonder how foreigners can ever start a business here". The same Tata a few years back had trouble establishing a factory for the world's cheapest car and have to move his factory around because the state government just wouldn't allow him. There is a NatGeo mega factories episode about this. I could go on and on.. (I am Indian myself and have spent 30+ years in the country)

Better logistical infrastructure in those countries than India. Moreover india is focused on an ICT strategy than an industrial one. But personally I believe it is because the companies that are moving are trying minimize disruption in the supply chain. A lot of the manufacturers have sister plants in those countries but not India.

Bureaucracy. In Vietnam you speak to one person for all governmental matters. Licenses, taxes etc. India has infinite layers that the company needs to navigate themselves and they are shit out of luck if they screw up one. In Vietnam their POC will help them navigate through the processes

Because India is not business friendly. It is a nightmare to buy land and get a factory going

Call centers: "am I a joke to you?"

India is a poorly governed country that is super populist and anti western from sentiment about colonialism. It has a poor and uneducated workforce. It is a federal country so you have to deal with political issues at a state and national level as a company. It is not ethnically homogeneous so hard to get consistent workforce at lower levels (e.g. not everyone will speak the same language). Basically India is a poorly governed lower middle income country that isn’t very attractive to corporations. I’m pretty sure it has a history of nationalizing stuff for populist reasons too

Favorable taxes and financial incentives, favorable labor policies, favorable laws around foreign investment, and electricity (bizarre but true). This is not a recent phenomenon. Intel set up a fab in Vietnam long back, a lot of consumer goods manufacturing has been in Thailand and Vietnam for 2+ decades now.