Mar1217 said:

PS : Pikmin 4 was Hey ! Pikmin all along. Why do people still persist in believing otherwise ...

One month before Hey! Pikmin came out they said "We can confirm that Pikmin 4 is in development but that is all we can confirm at present." So it wasn't the same game, but it's obviously going through development hell or been cancelled. As back in 2015 Miyamoto said "It's actually very close to completion."

So they weren't the same games, whether Pikmin 4 is still in development at all, or has been restarted from scratch, or the same project is still slowly struggling on? dunno.