As someone who has interviewed and worked with a number of international students with master's degrees, approximately 70% of them somehow manage to get a master's from a US college without actually knowing anything, so my cynical side says we definitely should not automatically add green cards to master's degrees.
The reason to give almost anyone working a tech job a green card quickly is so they don't depress the market wage by being indentured serfs.
The absolute worst thing the US could do to the Indian IT sweatshops is to give a "tech worker" a guaranteed green card in 18-24 months so that they can change employers. Those companies would quit applying for visas almost immediately.
Need a source for this. I'm sure there are a vast number of master's students who get their degree from shitty colleges to just be able to work here, but the vast majority of international co-workers I've had were amazing.