I think Disneyland's biggest focus will be on their upcoming anniversary and something tells me that they will indeed have a new parade in the works in honor of the celebration.
In recent years, Disneyland typically keeps a parade for several years (5 years or more) before developing a new one. For example, Soundsational was from 2011-17 and returned in 2019. Parade of Dreams was 2005-08, Parade of Stars 2000-04. In the case of Magic Happens, it opened for barely weeks in 2020 before the parks closed for the pandemic. And did not restart until in 2023. So it is really a pretty new parade still. Used about 2 years when you factor in the holiday parade taking over for periods of time. I happen to love Magic Happens and have hopes it will be returning in 2026.
Paint the Night (best nighttime parade ever) has been announced as returning for the 70th. I am thinking there is just not the space to store the floats for both Magic Happens and Paint the Night, and that once Paint the Night goes back in the vault that Magic Happens will return again.