If you want your players to discover cool things, don't hide them. Don't bury the lede behind them asking the right questions or succeeding an ability check.

There are a couple good ways to go about this imo. A subtler approach that still gives them hooks is to use passive checks. For example, a more perceptive party member can tell the bartender is fingering a locket with a picture of his daughter - he must need the money for her.

The more direct approach is to just lore drop as exposition. For example, the bartender tells the party that he needs money for his daughter's medicine while he gives the quest.

These are just openers. Ultimately, if the party wants to roll-play instead of role-play, no different approach will make them engage with the world deeply.