I have seen bookstore (second-handed books) thriving near universities. Your idea is actually very interesting and remind me of the mall model -- the mall model worked because everyone in the family gets his/her own share of pleasure. Of course the traffic matters a lot, too. Hope you start that experiment soon and succeed!
The general theory of most malls was that you had anchor stores. My local one has a couple of stores adjacent to the mall (a local chain supermarket and and Home Depot) that are very busy, almost too much so. The mall itself is pretty much dead and has been on the market for ages. The anchor stores--JCPenney, Sears, and Macy's are all long gone. Haven't been in the actual mall in ages but I assume it's pretty sad and there seem very few cars in the lots.
Oh, yeah, the Toys 'R Us in the complex is long gone too.
Universities are effectively ultra-anchors. You have large numbers of students from mostly middle class backgrounds, many of whom have free time and disposable income. (Or at least they're not worried about their loans yet.)
And then you have the academics. Tenured profs are relatively well paid. Adjuncts/assistants not so much, but they still like nice things.
The UK's public school towns (Marlborough, Harrow, Winchester...) often have a prosperous independent store economy on a smaller scale, for the same reasons.
Clusters work well in these towns.
If you try them elsewhere, like one of the UK's many run-down towns, they're more likely to fail because the prosperity just isn't there.