Oh no, it’s not that simple... First of all Zoro actually saw the fire cutting style demonstrated. Then he expressed interest in it, 300 chapters ago. And it is canon that Zoro trains EVERY SINGLE DAY
There’s 3 things here. It was foreshadowed, Zoro trains every day, and he saw it demonstrated and wanted to learn it.
This isn’t a random thing that someone never expressed they could do or wanted to do or even had the means of doing.