Super Mario Bros. 3 Happened, And Wasn't Just A Stage Play
So many people believe that the events of Super Mario Bros. 3 never happened and it is all just a stage play, I am going to argue why this is not the case.
First off the Airship from SMB3 exists in another game, aka Super Mario Bros. 4 Super Mario World. Confirmed in the manual on page 20, the Sunken Ship is the same Airship from SMB3.
"This strange looking sunken ship. Haven't you seen it somewhere before? That's right, in Super Mario Bros. 3..."
Secondarily in Donkey Kong Country: Tropical Freeze the level Frosty Fruits contains a SMB3 Koopa Tank. This also means that Bowser or at least the Koopas once invaded the Kong Archipelago.
So these 2 things should be enough evidence that SMB3 is indeed a canon game. However, for argument's sake let's say SMB3 is a stage play. There is nothing saying that the stage play can't be based on actual events that happened in the Mario canon. Some more reasons SMB3 is canon is objects and characters that were introduced in it, still exist in the game canon and show up later. This includes Dry Bones, Boom Boom, Boss Bass, Fire Bros, the Clown Car, the Koopalings, and the Airship.
This is actually backed up on page 35 of the SMB3 Manual where it says.
"A host of new characters have joined Bowser and his turtle tribe. With this information on these new enemies, you'll be well prepared."
Speaking of manuals, in the SMB4SMW manual in story section on page 2 it says "after saving the Mushroom Kingdom from Bowser and the rest of the Koopas in Super Mario 3, Mario and Luigi needed to recuperate from their adventures. Together they agreed the best place to vacation was a magical place called Dinosaur Land.."
This places the events of SMB4SMW right after SMB3.
Written by Eris the Lorekeeper
Other references that confirm SMB3 events did happen.
Super Mario Sunshine
Bowser's Memories
The Grasslands
Desert Land
Figure-8 Circuit
DS Shroom Ridge
DS Desert Hills
Piranha Plant Pipeline