"Board games" covers a number of game genres with great variance in both set-up and play time. So does "roleplaying games". Most generalized "board games versus roleplaying games" hence only serve to demonstrate the person making the argument has not played enough different board and roleplaying games.

To put some perspective to things: Finnish roleplaying convention Ropecon held a scenario design contest for years. Design goals for these scenarios included that a game group can pick them up with no prior knowledge of a game system, learn the relevant rules in 15 minutes and play through the scenario in 1 hour.

This is one pool of dozens of short roleplaying games, if a short roleplaying game is what you want. If they don't make a splash in these kinds of discussions, it's ironically because they're distributed for free under license by a non-profit organization, instead of being put in a neat box and marketed with big money by a toy company.