I know...there are smaller marketplaces that people can buy/sell goods via bitcoin, but why a major marketplace is not emerging??
I know for a fact, there is a huge demand for purchasing of goods with BTC...even users from this forum is enough to give the marketplace a supply chain issue

1. is the problem in supply side? are sellers worried taking payments via BTC bcas of volatility
2. is there a logistically inefficiency, that smaller sellers can never compete with the likes of amazon
3. is the transaction speed an issue for retail transactions?? major cards payments are done instantly (maybe this speed is needed for impulse purchases

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Comment below...thanks i'm a newbie here

There are three major marketplaces: Ebay, Amazon and Aliexpress. They have their own payment system that's their priority: Paypal for Ebay, Amazon pay for Amazon and Alipay for Aliexpress. Logically bitcoin doesn't seem to look like their friend but what if demand is huge? Real answer is that demand isn't that good to implement bitcoin or any other cryptocurrency and at the same time it's not easy decision and when you are a huge company and want big to implement something big (yeah, bitcoin is payment way and amazon has a lot of transactions daily), you have to keep things legal and fair. Government's answer on facebook's libra is something that major marketplaces have to consider if they think about cryptocurrencies. There should be other plans too, for example how to do refunds, how should it be done? How will we verify users' bitcoin adresses? How will we get rid of money laundering? And many other questions that they have to answer. In overall pros have to outweigh the cons.
Some marketplaces aren't supported by cryptocurrency depending on their locations because there are some governments that prohibits the use of cryptocurrency in many transactions. Most of the major marketplaces uses fiat currency as payment and I don't know any market that allows bitcoin to regulate in their business. There is a possibility that volume of people that uses bitcoin is also a factor on why markets are not allowing people to pay with bitcoin because not all customers have it. Hoping that governments should consider people who are using btc in their country, they should study and understand how btc works on the economy so that they know the benefits of it and start promoting mass adoption in its community.