At the absolute very most - realistically it’s nearer to 18mins…
You can get there even quicker at 69.7MPH 
But yes, in all seriousness, I see your point 
Why would you want to upgrade from the Mavic 1 to the Mavic 2? (or even the Inspire for that matter) Does it / they offer you (personally) something you’re not getting from the MP1 or the Air? 