Because the TAM of people who want books is a lot larger than people who want pet supplies, and there are compelling reasons why people would rather buy books from centralized warehouses than local inventories (namely, that books have a long tail and pet supplies do not).
This makes 0 sense. What makes you think the market wasn’t already adequately serving people who wanted books? New technology is the only reason this sales pitch worked. It’s not enough to provide books. You need to provide more books at cheaper prices than existing incumbents. Without knowing the competitive landscape, you can’t say whether or not selling books is better than selling pet supplies.
Types of dog and cat foods are more substitutable than book titles, which decreases the value proposition of warehousing a larger variety.
And on the profit side, books don't spoil and are small and light.
Bezos is on record in an interview somewhere as saying that he didn't care what they sold on the internet -- they picked books (and later music and movies) because they were good fits to store and ship.
> Total addressable market and value proposition are key.
> A specific technology doesn't really change either of these.
Bezos chose books because they ship well. This is because he was going to use a new technology (the web) to sell goods and needed items that would work with this model well. So the decision to sell books had little to do with TAM and everything to do with technology. Basically the opposite of what you originally asserted.
Technology can't create a value proposition where none possibly exists.
There was no Pets.com business model that would have worked, with any technology shy of a free energy transporter.
In contrast, Amazon proceeded thusly.
1. There are a lot of people who buy books.
2. People who buy books would value a wider selection. (than current local options make available to them)
... therefore, what combination of technologies exist that allow Amazon to deliver on the above? (web storefront + centralized warehousing + efficient shipping)
The point of bubble businesses is that the first two components, neither of which have much to do with technology, are often absolutely missing.
Fundamentally sound business plan + new technology >> ?? + new technology
Too many bubble businesses are the latter, and people invest in them despite the ??.
Rationalize all you want but Amazon's retail arm still turns a loss, minus platform ads. Bezos realized early on that the bread and butter of Amazon is AWS (and Amazon software in general), and that's what's keeping the retail arm stable.
From a revenue perspective though, your argument is prudent. Maybe targeting books rather than pets helped it lessen its relative burn rate.