I can't see where on that link it talks about the nib developing flatter surfaces. The nib is flexible and with long term use and excessive pressure can alter the angle of the tines. That can affect the ink flow through the slit affecting how the ink is laid.

The tip, the only part which touches the paper, is made of iridium[1], or similar, which is very hard. As far as I can tell that doesn't wear. Some very old or specialise/custom nibs may use softer metals and perhaps wear would be a possibility on those but in any instance I can't see you wanting a flat spot to develop.

[1] It turns out that modern iridium nibs probably aren't made of iridium. I was looking into wear on them and found, amongst others, this https://www.nibs.com/blog/nibster-writes/wheres-iridium which does into detail analysing the composition of a fair number of nibs. Down the rabbit hole!

“As the material is soft enough to adapt to your handwriting with time.”

Not every nib is flexible. My Duofold and Meisterstück certainly aren't, my cheap Noodler's Ahab just to a limited extent (but it is a special steel flex nib).