Smartphones are eleven years old so if you had been asked that question two years ago you would have been talking about the fundamental change in how most people get most of their internet time through a technology that isn't even a decade old.
I agree with smartphones as the fundamental change. But what else in the last 10 years?
People getting a majority of goods, services, and customer service centres via online or automation. Fall in use of hard cash in favour of card (often contactless) or online/app transactions.