Exactly these mom and pop store do not have enough marketing and trained personnel to sell Nike brand of shoe. It is right that Nike cut them down. Alternatively, Mom & Pop store can market product from China.
They can sell Weights, equipments, Jackets , shoes. There are whole lot to choose from. They can sell brands from China too.
The same thing happens every time market share shrinks - small guys die off first and the big guys consolidate power. Only the fast moving small guys will survive to fight another day.