Consider also how dramatically sea level changed just as human civilization was coalescing. The North Sea was dry land, connecting the British Isles with France and Norway. Southesast Asia was much larger, with much of the sea separating the Indonesian islands from the continent dry land.
Then consider that through most of human history coastal areas have been the most intensively settled because of the transportation and foodstocks the sea provides. So, for most of mankind at a very formative period, the rise in the sea must have seemed relentless as the glaciers melted.
An awful lot of our archaeological history is under the sea.
Saw a how TV show where they were going to old river deltas looking for artifacts either by diving or dredging. they had not yet made any great finds but some things that were promising.