>and Amazon's sole advantage is product placement, is it still problematic?
Potentially, but stop focusing on the act and focus on the result.
You brought up retailers and their shelf space. First no grocery store puts "Grocery Store O's" in a better placement than Cherrios...but fine lets assume they did. Does putting "Grocery Store O's" force Cherrios out of the market? No. However, seems to be no shortage of examples of a successful vendor on Amazon being forced out of the market altogether after Amazon copies their successful product.
Potentially, but stop focusing on the act and focus on the result.
You brought up retailers and their shelf space. First no grocery store puts "Grocery Store O's" in a better placement than Cherrios...but fine lets assume they did. Does putting "Grocery Store O's" force Cherrios out of the market? No. However, seems to be no shortage of examples of a successful vendor on Amazon being forced out of the market altogether after Amazon copies their successful product.