As a grad student I took out a student loan for the equivalent of a year's stipend, to buy an Apple II in 1980. Within a week I voided the warranty (?) by carrying out a "shift key modification" that involved cutting a trace on the motherboard.
It worked, so I'm a bit baffled by Woz's explanation.
The Apple II didn't really advance my math research (that would be the later 128K Macintosh, to which we ported the Macaulay computer algebra system), but various friends learned computers at my apartment, shaping their later careers. The Apple II remains my only computer whose memory layout one could understand byte for byte.