Not just that, but also encourage people to actually do the star chart. Noticed that a few people got kind of stuck around Mars, just because the game lost momentum.

Basically, they haven't played enough to "get" the fun from trying out new weapons, frames, mods etc. and there's not enough story reason to continue.

Doesn't even need to be a fully cinematic quest - Natah wasn't cinematic but set up Tyl Regor fantastically. If each planet before Saturn/Uranus had its own "Natah" to point at the boss, the early progression would flow much more nicely, especially if it hands out some essential mods and early weapon blueprints to nudge the player into experimenting.