Yes but few did it digitally.
Yes. Because there were only a few people using the internet at the time. When Amazon got founded as a digital book store, number of internet users globaly was 16 million. By the end of 1996 it reached around 40 million global internet users.
There were digital book stores before Amazon, and some existed alongside Amazon when they were founded. Unlike others, Amazon expanded its business from just selling books to other items and that is why we still know Amazon and not the others.