Why is the second one a better proposition?
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.
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 ??.
The Pets.com business model is essentially the same as Chewy, which does work. As far as I know, Chewy has not discovered a free energy transporter.
Not sure what your point is regarding vet and pharmacy services. Businesses expand. Pets.com, had they been successful, would have likely done the same thing. To use your Amazon example: obviously most of Amazon's revenue is no longer generated by selling books.
From a revenue perspective though, your argument is prudent. Maybe targeting books rather than pets helped it lessen its relative burn rate.