I believe around the world doesn't imply visiting all countries, or did I misunderstand?

Visit every country in 72 days? A UN senior official might be able to manage it with one of these: https://en.wikipedia.org/wiki/United_Nations_laissez-passer , which would also provide a way round the mutually-exclusive visa rules. You might encounter some problems with defining a country (Palestine, Taiwan, Nagorno-Karabakh etc)

Physically it would be doable with a private jet and some helicopter transfers for the awkward cases. Microstates without airports (San Marino) and tiny islands (Sao Tome etc) might take up a lot of time.

(The Verne trip was a "mere" circumnavigation, immigration was a lot easier back then, and quite a lot of it was British Empire)

What's the takeaway if it was possible?

Do you count transit or must immigration be passed? If you think about this question, isn't it worth more to have a chat online with people from every country?

It's possible if you plan ahead; but that isn't what the author did.

I doubt this is possible. Maybe if you take helicopters to get from border to border and have all immigration officials ready to process you once you arrive.