There were a lot many years from the time of Amazon's inception till they became a monopoly. It seems like your "what could be" experiment has already been done. There was plenty of opportunity, but nobody managed to build a better competitor to them.
It is a separate argument, but 'more competition' isn't a magical fix to everything. This sort of gating mechanism relies on the end user/consumer having good knowledge, sound judgement, etc. Also what is best for the consumer isn't best for the society. A wild example - For me, as the consumer I'm happy to get an iPhone for $200, but that might mean that Apple pays their employees below US minimum wage.
It is a separate argument, but 'more competition' isn't a magical fix to everything. This sort of gating mechanism relies on the end user/consumer having good knowledge, sound judgement, etc. Also what is best for the consumer isn't best for the society. A wild example - For me, as the consumer I'm happy to get an iPhone for $200, but that might mean that Apple pays their employees below US minimum wage.