A lot of y'all are too young and just speculating. I am 47, and was 28 in 1988, and will give you my perspective. I don't think the race was huge with the general public, but it was pretty big. In those days, T&F, at least once every four years, was a bit more high-profile, and as has been stated above, Carl Lewis was known by EVERYONE, not just T&F fans, in the U.S. He was the most recognized track athlete since Jesse Owens in 1935-36, and deservedly so (deservedly in terms of his accomplishments, not in terms of whether he may have been juicing or not). He was not the most "loved," but certainly the most well-known, and as it is with Americans, everyone with an interest in the Olympics wanted him to win because Americans ALWAYS root for the USA in the Olympics. But was the race something the average person remembers like the moon landing or JFK assasination? No, just another race. I'm sure it was a much bigger deal for Canadians.
Now the Johnson positive test, yes, that was big time. The triumph of the American sprinter over the Canadian cheater? Restoring order to the Universe! Everyone remebers that with relief and pride. Never mind that many people close to T&F have strong opinions on Lewis' drug use, especially in the early 80s, the summer of 83 in particular when his face got so puffy. I mention this as context, not because I feel strongly one way or the other about it, or have any personal knowledge.
Now, from within T&F people, the race was HUGE. I was in Moscow in 1986, a member of the Goodwill Games team, and was in the cavernous Olympic Stadium near the Moscow River with a great seat for the 100m final. I was stunned when Johnson won. A fluke! I hadn't seen Lewis lose a race since 1980 in Eugene when he was about 19. My first thought, and it was spoken by many that night, was Johnson must be using some powerful dope to beat our King Carl. The next summer, leading up to the IAAF in Rome, I was in Germany training in August, in a sports complex in Dortmund before joining the U.S. team in Stuttgart, and we were able to watch the European meets like Zurich on TV, great coverage. Big Ben was tearing it up -- 9.97, 9.95 every time like it was nothing. It looked like Carl would need a great start and a 9.90 to win in Rome. I did not see the 100m final -- I was outside the stadium racing the 20k walk on a road loop when the 100m final took place, and then we finished on the track about 30 minutes later -- but his win in Rome was a major bummer. So I remember vividly watching the 100m final in 1988 at my friend's house in Colorado Springs , hoping for a miracle by Carl,(I had failed to make the O team in the 100-degree heat and humidity of Indianapolis) and the disappointment I felt when Ben won again. The next day I was on the roof of my house near Cripple Creek fiddling with the antenna when my wife came out and told me Johnson tested positive and would be stripped of the gold. I nearly jumped off the roof for joy. "I knew it all along!" I shouted.