Nickstates

From “Slang in America” by Walt Whitman (emphasis mine):

It is curiously in embryons and childhood, and among the illiterate, we always find the groundwork and start, of this great science [slang], and its noblest products. What a relief most people have in speaking of a man not by his true and formal name, with a “Mister” to it, but by some odd or homely appellative. The propensity to approach a meaning not directly and squarely, but by circuitous styles of expression, seems indeed a born quality of the common people everywhere, evidenced by nick-names, and the inveterate determination of the masses to bestow sub-titles, sometimes ridiculous, sometimes very apt. Always among the soldiers during the secession war, one heard of “Little Mac” (Gen. McClellan), or of “Uncle Billy” (Gen. Sherman.) “The old man” was, of course, very common. Among the rank and file, both armies, it was very general to speak of the different States they came from by their slang names. Those from Maine were call’d Foxes; New Hampshire, Granite Boys; Massachusetts, Bay Staters; Vermont, Green Mountain Boys; Rhode Island, Gun Flints; Connecticut, Wooden Nutmegs; New York, Knickerbockers; New Jersey, Clam Catchers; Pennsylvania, Logher Heads; Delaware, Muskrats; Maryland, Claw Thumpers; Virginia, Beagles; North Carolina, Tar Boilers; South Carolina, Weasels; Georgia, Buzzards; Louisiana, Creoles; Alabama, Lizards; Kentucky, Corn Crackers; Ohio, Buckeyes; Michigan, Wolverines; Indiana, Hoosiers; Illinois, Suckers; Missouri, Pukes; Mississippi, Tadpoles; Florida, Fly up the Creeks; Wisconsin, Badgers; Iowa, Hawkeyes; Oregon, Hard Cases.

Why didn’t all of these become the names of college  sport teams?