Another contributing factor is that players can’t withdraw or spend chips from the economy. There’s nothing to purchase with the chips. Maybe there could be custom avatars or badges or something like that.
I think that the various leaderboard competitions are an attempt to address measuring skill in a more valuable way - e.g. Hold Em Hustle is counting the total number of BB won by players this week across different levels of table. It would be much better if these competitions ran all of the time (maybe both weekly and monthly leaderboards) instead of sporadically. It would also be nice if they were made a bit more prominent - e.g. showing a player’s rank in the relevant competitions at the table being played as well as or even instead of their overall bankroll rank.