Andreesesen is overly celebrated because of his extreme luck, and is certainly not the first. Look up John Bardeen and Nick Holonyak for examples.
My posts were meant to highlight entrepreneurship which is why I didn't mention them (they'd be in a class of amazing innovators who studied/worked at UIUC). There's also a ton of awesome alumni that have gone on to be C level execs at big companies, but again they were omitted because these posts were specifically targeted at entrepreneurial alumni.