Why people play Unranked over Ranked:
1.) No rank restrictions, so faster queues
2.) Same reward for way less effort required
3.) Nobody's rank is on the line, so low pressure
4.) Easier to have fun if you sit on the higher end of skill in a match

If Ranked has a bunch of restrictions and pressure points, you need to incentivise it.

Right now the most active Ranked players are those who already are at the high end of the skill gap, seeking occasionally intense matches. Or they just scrim in Custom Match for 3rd Party tournaments.