Technology is exponential, it builds on itself.
I would actually say it all started around the (late) 1800's (Letters -> Telegram -> Phones -> Cell). What was in that time period? Oh, the Industrial Revolution, which increased production, the active working hour (lightbulbs) , increased speed of communication (large scale literacy, telegram), etc. All these inventions made future invention quicker, easier, and more wide spread.
"Modern" inventions required great infrastructure to be made - infrastructure only developed after the industrial revolution. The electric grid, the internet, even to some extent cities and roads.
Relatedly, its pretty hard to grasp an entire new, revolutionary tech, than it is to expand on it. Once computers existed, it wasn't too much effort to continuously improve them, doubling every two years. It's pretty easy to see the snowball in the information age.
And glorious capitalism in its current state only really existed after the colonial era, and we know what market forces provide. Businesses, not just governments, have big incentive to innovate and expand as much as possible, so they do. Credit, largely adopted by the 1920's, also boosted the economy to incredible heights (and depressing lows), and allowed the common folk of the first world to get and use new tech (promoting development of newer tech, and the first major QoL change).
Also came the agricultural revolution and a booming population. More people = more ideas, more inventors (though both world wars put a dent into that)
tldr: industrial revolution and capitalism in many words