I understand not every decade was a clean break, but each decade has fairly distinct defining properties. It feels like most of the 21st century has been a single run on with smaller changes. I know sometimes the definitions don’t come into focus until later, but I’ve been around since the 80s and I can distinctly remember the changes between the 80s, 90s and 00s as they were happening.
I mean an obvious break in the decades was covid. There has been a fair amount of shift in a lot of different things pre/post covid that maybe doesn’t stick out due to the gradual shift, but will definitely be more apparent to anyone looking back on the 2010-2030 time period.