Incentive works, for max level content. For low level content, if the sync feature is as bad as on XI (i.e. you do need the right gear otherwise your stats are bad since the scaling is done wrong), then people wouldn't bother to help.

I won't keep a set of level 20 / 30 / 40 gear just to be able to help random people. Inventory is already an issue with lv max gear alone.