Anecdotally - it just does not at all feel this way when talking Iowa City. THAT college town feels very much in sync. It sure feels like some college towns definitely have a symbiosis relationship, and Ames simply does not. But yeah, could be perception/bias/etc. influencing opinion.
To the extent that your anecdote is true, that might be because of the hospital. Because of its presence, Iowa City is closer to being the same city year-round (not that it doesn't change, but just less so). Whereas Ames is a completely different city when classes aren't in session and has many of the advantages (a lot of businesses, beautiful campus, etc.) without some of the disadvantages (busy gamedays, traffic, lots of pedestrians, etc.).
Basically, there's a time of year when Ames residents seem to experience what the community would be like without the college--except, of course, they don't because if the college didn't exist, many of the things that make Ames extra enjoyable in the summer wouldn't exist in the first place.