A question about defenders, not shooters
The common description of spacing is that teams shoot from distance, which mistakes the symptom for the mechanism. Spacing is really about obligation: if a defender must stay attached to a shooter beyond the arc, that defender cannot also stand in the driving lane. Every credible outside threat removes a body from the area where most efficient shots are created. The shots themselves are the visible result; the redistribution of defenders is the actual work.
The threat that never has to fire
This is why a player who takes few shots can still be central to an offence. The threat is priced in by the defence in advance, and the space it creates is used by someone else. Judging such a player by personal scoring badly misreads their contribution, in the same way that judging a screener by points would.
When spacing collapses
Bad spacing is rarely one obvious error. It is usually two teammates drifting into the same area, which lets a single defender cover both and turns a two-on-two into an effective two-on-one for the defence. The drive that looked correct when it started arrives into a crowd. Fixing it is a matter of habits and floor discipline rather than talent, which is why it is one of the fastest things a good coaching staff can improve.