And just like that, I've gone from happy and excited to sad and mournful. :(

All of Europe is Sonyland!
I'm surprised I didn't see something like that when the Games were in London 4 years ago!

But anyways, this was an obvious, but brilliant move on Nintendo's part to push for Mario to be the main mascot of Japan for Tokyo 2020!

No one outside of game fans of this generation know who Nathan Drake is. The Olympics are a global event aimed at people of all generations ... Mario transcends video games, as popular as the Playstation brand is they don't have any singular character property iconic in that way. 

Very true.
While Sony and Microsoft don't have even one character like that under their banner, Nintendo has PLENTY of them.
Expect to see not just Mario in the Opening Ceremony in 4 years, but don't be surprised if Luigi, Peach, and Bowser join him!
And I'm expecting to see quite the large number of Pokemon their as well. They'll mostly be Gen 1 and Gen 2, but still.

Awesome move by Nintendo. Looking forward to seeing how they build this up as the next Games approaches.

Well, they have their theme park with Universal scheduled to open at around the same time that the Games start, obviously looking to cash in BIG on the tourism!!

Love how the pipe stayed right there throughout the Tokyo dedicated part, and how the Mario 'course clear' fanfare played when the fireworks went up

That's great, I kind of regret not staying up another hour or two to watch the closing ceremony...

That's so cool :D It's really awesome that they have a video character to represent Japan's Olympics next time around.