That interview is included on a 60-minute album recorded by Davenport's Dick Lamb back in the early 60s. It's called Hooray for the Hawkeyes! and it may be the finest sports highlight recording ever made. It primarily features radio and TV calls of Iowa games during the Evashevski era, from about 1952-1959, tied together by Lamb's eloquent commentary. If you're a Hawkeye fan, you should find it (try contacting WHO Radio in Des Moines) and devote an hour to it. Toward the end it includes Kinnick's Heisman speech in its entirety as well as the interview the OP references. Here, verbatim, is what Kinnick says in that 1940 interview:
"Rightly or wrongly, football is very definitely tied up with the status of the university. The majority of people who go to college don't get that wider variety, they don't get that better mental equilibrium, they get the opportunity. And I think the same thing is true about football. While possibly the majority of the boys don't get those subjective values I mentioned, certainly the opportunity is there, and I think that the values they do get are, perhaps, more intensely brought out than they are in the educational system itself. As far as any activity that I've been connected with or concerned, football has given me the opportunity to round out my philosophy, to change my thinking process, and that sort of thing, has done more for me along that line than any other activity with which I have been connected."
It's great that Iowa plays a snippet from Kinnick's Heisman speech every game, but it doesn't begin to convey the intelligence, the eloquence, and the rare leadership embodied in a young man who was destined for greatness far beyond the football field had not fate so cruelly intervened.