When online mapping was first around the javascript slippy map hadn't been invented. The page would show you a given map tile, and provide left/right/up/down/zoom buttons that would load a tile one step in the direction you chose. Sometimes with a complete pageload for every step.
For example: https://web.archive.org/web/20040805053745/http://getamap.or...
Google maps was still years away. And tile server tech wasn’t quite there to ship it yet. But it was the obvious thing to build, and not in any way a mystery as to how you’d do it.
Inventions are often that way -- think of the mousetrap. People knew springs pinched the crap out of you when released. But nobody had made a device to kill mice, yet untilthat was invented.
I don't know what the cognitive bias for thinking that because you thought of an idea it must be obvious is, but it exists. I say that as a patent inventor.
The technical "how" of the implementation is not really obvious, you could implement the same result in many possible ways, some better than others.
Technical and business limitations drove the design of MapQuest. That client computers had little computing power, bandwidth (on both sides of the pipe) was limited and expensive, and processing power on the server for a very low value user (per interaction) had to be meted. No one who used MapQuest didn't wish they could just smoothly scroll the map, but we were fine given many of us were on a terrible connection, ran on systems with limited graphics power (where even smoothly blitting a high resolution raster graphic was taxing), etc.
Every improvement (more computing power, memory, storage, bandwidth, or even business model, etc) in the industry invariably leads to many people all independently seeing the same obvious next step, many groups building the same eventual thing, and then the losers (from a market perspective) claiming that their ideas were stolen. It is the story of this industry.
Perhaps you could interpret the parent comment as "if you're doing online mapping [and mouse drag/drop is possible in the browser], the first thing you think of ..."
There were also other interesting navigation schemes that relied on multi button mice or tablets.
I still like the model where you hold down a button and the navigation speed and direction is controlled by the distance and angle from that click point to the mouse cursor.
I think "grab to move" is as old as our opposable thumbs. There is nothing innovative about it
