EDIT: spelling
"Shu noticed that since the Great Recession, after Wall Street careers had lost of some of their luster, newer classes of MIT students became more likely to major in science and engineering subjects — and their grades were better, too. This effect was most pronounced among the weaker students. Shu has a hunch that some students had been slacking off in their classes because they anticipated working in finance, not science, after graduating."
I'm an undergrad CS senior signed for a quant/programming job at a Wall Street trading firm after I graduate in a few months.
I have several friends from previous internships going to work at the same company after they graduate. None of them (nor me) matches the description you gave. Many of us are involved in research at the undergrad level, and no one is coasting by on the bare minimum. Some of these people are also not the sort of people who make any effort to network. The common thread seems to me to be a very strong theoretical and professional background.
Of course, this is with a sample size of 5 undergrads and 1 company, so what I'm talking about could be highly atypical.
Also, if you like doing the bare minimum, you're going to have a bad time in Wall Street, because they often have a bad culture of working 50-100 hour weeks (depending on the company). That's the cost of the more attractive compensation.