Okay. You're right about what I wrote. Let me rephrase what I meant. I was missing the words "the widespread adoption of"
Athens had a democracy over 2500 years ago. A few Native American tribes had long-lasting democracies. Ukrainian cities were democratically self-governing 500 years ago, and Poland had elected kings.
Those were isolated examples. This was not a revolution. We also haven't regressed; isolated examples continued throughout history. If you point to a year, you can probably find some democracy somewhere. The only major regression I know in history was around 1000BC. Regressions are rare.
What changed was a revolution. From just before 1800 to just a little after 1900, virtually every country had a revolution which led to either being some form of democracy, or pretending to be one. Democracy was no longer isolated. We had the creation of a free world covering much of the world's population, and the creation of what was pretending to be a democracy (today, even the Democratic People's Republic of Korea pretends to be a democracy).
The number of countries which claim to not be a democracy, you can count on your fingers. Iran. Vatican City. Saudi Arabia. UAE. Oman. Eswanti. Did I miss any?
Progress isn't inevitable. It's possible for knowledge to be lost and for civilization to regress.