However, I could be wrong but I believe that the Olympic trials qualifying time for the 1984 US trials was 2:19:07 which I think was based on the 100th fastest time in the US either the year before (maybe it was the previous Olympic year but I don't think so)... In any case, I don't think 2:20 was all that common back in the 80's...
Of course, I don't think 2:20 is the equivalent to being a pro in the NFL, NBA, or MLB... maybe you'd need a sub 2:17 for that.
But, as the name suggests, it's not all that important...
cheerio mates