As someone actually on a green card, working at one large tech company and previously at another where I got the card (both in the same range of importance as M

As someone actually on a green card, working at one large tech company and previously at another where I got the card (both in the same range of importance as Microsoft), and having seen various colleagues go through various issues: no, it really does not work that way. For instance, my card was delayed for something like 2 years, because anything immigration related was extremely slow in 2002... The main benefit you get is good quality lawyers who make sure you do the process the right way.