Are these other projects more interesting/lucrative though? If so, I struggle to see why they turn up at the one that apparently isn't?
Some people are just bone idle and there's no motivating them. I manage that by not being in the same room with them.
If you can see my sig, you'll see that I'm in four bands and dep in two others.
Most of the people I work with are the same. The one thing they all have in common is they love playing the music.
Without that, you're on the back foot from the start.
As @Lozz196 said, dedication + application and turn up with your game face on every time.