I think Nintendo never allocated altogether so much presentation time for one video game before:
Direct March 2018: 1 minute
e3 2018: 25 minutes
Direct August 2018: 27 minutes
Direct September 2018: 3 minutes
Upcoming Direct November 2018: 40 minutes
Totaled up Smash aired on Nintendo presentation (excluding Treehouses): 96 minutes
They did it before with Smash 4.
You had E3 2013's initial Smash Reveal (+ Wii Fit Trainer's reveal), Smash Direct in April 2014, E3 2014 (along with the subtle Pac-Man reveal at a closed door presentation), Smash Wii U's 50 Fact Extravaganza, the Mewtwo, Lucas, and Smash Ballot reveal in the April Fool's Direct 2015, New Smash Content at E3 2015, Cloud's reveal in the November 2015 Direct, and the final Smash 4 Presentation in December 2015. Don't have time to sum up the total amount of time, but it's extensive.