Super wealthy people can ski all they like, but a ski bum is someone who sacrifices having a "real" job in lew of seasonal work so they may ski all winter. Not all, but most are poor because it's hard to make a lot of money with just seasonal work. Ski bums live very frugally because they have to in order to survive. They are not trust fund people, or people with tons of money. They are people who don't think about what they are going to do when they get old and can't work or ski anymore. They may or may not have a retirement plan. Some may hope to get a large inheritance in their older years to finish their lives, but until then they put a priority on skiing and not on making a ton of money. They make HUGE sacrifices to ski compared to a wealthy person.
I hope that helps. Just because some dudes ski all winter does not make them a ski bum because they are well to do retired people whether old or young.
Good luck on the mission.