Conventionally, when we need something, we visit the market, enter the shops, and ask for our commodities. But with shopping apps having come up, all we need is just look up the items in our mobile phone, click on it, make the payment, and lo! in 10 minutes the door bell rings and the commodity arrives. Isn’t it the exact relation between a server and the client ??
You said that online shopping has existed since 25 years… Wait a second… That’s after Y2K, right ??
I said over 25 years, so before Y2K.
Doesn’t matter. It didn’t become prevalent until ~10 years later, at least where I live.