I've run an ecommerce business for over 25 years, I also contract work for other organisations when asked in ecommerce because no one pays the staff enough in this to get the people who have the experience to do it.
Ecommerce is not actually a new business structure, it is a form of marketing, we have had forms of distance selling for centuries, it is the technology that is used that is new. Like other distance selling, ecommerce is just part of retail and a small slice of the whole retail industry. For example in the UK in the last 2 years it forms under 27% of the retail industry, that includes the likes of Amazon and Waitrose as well as individual businesses like mine.
In many ways ecommerce slotted into the space niche shops had on the high street, the hobby sector looms large in this, and while some gave up their shops due to costs and rates, many just replaced their distance selling operations with ecommerce as a form of marketing and continue in their shop or office.
The death of the high street was set way before 2008 when ecommerce started to be interesting to supermarkets and John Lewis etc, prior to then we early adopters of this form of marketing were called cranks and fantasists within the industry.
The high street has ben devoid of small independants for decades, some hung on but almost all the high streets across the UK became a replica of each other as the business rates, parking costs, public transport woes and shop rents drove customers and individual small businesses away.
For me the really interesting thing that happened was there are few qualifications or skills in ecommerce/digital marketing that actually work. The larger organisations still have to get the likes of me in to upskill or write reports on their operations so they can fill in the gaps. It also meant that while big hitters like M&S are online, an individual business like mine can climb way above them in the search engine ranks simply because of our knowledge and experience. In many ways the internet has become the great leveller because it doesn't matter how much money and people they can throw at ecommerce, some little enterprise that can move quickly, work flexibly, and has enough experience to stop their niche being subsumed by these big businesses.