Amazon has been quite cautious in its roll-out of Amazon Go stores that replace the cashier with a smartphone app. When you're trying something so different, especially when the general public is involved, it's wise to do so. However, that could all change in the coming months as Amazon is thought to be considering opening thousands of new Go stores over the course of three years.

As Bloomberg reports, "people familiar with the matter" suggest 3,000 new locations are planned, but CEO Jeff Bezos still isn't certain which direction to take the Amazon Go concept. Should it be a convenience store with fresh food and groceries? Or more of a fresh-food focused experience where you drop in to grab lunch?

Right now, there are three Amazon Go stores in Seattle (7th & Blanchard, 5th & Marion, and 300 Boren Ave N) and one in Chicago. Back in February, we thought there could be seven by the end of 2018.

If Amazon intends to get that total up to 3,000 by the end of 2021, it needs to be opening 20 new stores a week from the beginning of 2019 onwards. That seems overly optimistic even for Amazon, especially when you consider each store requires roughly $1 million worth of hardware in order to function, then you have to secure the retail space, hire and train the staff to work there, and ensure the supply chain is setup to keep the shelves stocked.

Amazon Go is seen as a competitor to the already well-established chains of 7-Eleven convenience stores and Subway fast-food restaurants. However, even if Amazon did achieve 3,000 new Go stores by 2021, that would still fall well short of 8,400+ 7-Eleven locations and 26,000+ Subway restaurants spread across the US.

If Amazon manages to open 1,000 new Amazon Go stores by 2021 I'd be impressed. But that would still require nearly seven stores a week open from January 2019 to achieve.