Timeshare as a concept isn't a scam. But pretty much any company you meet selling it is.
Collective ownership of a holiday property can be enormously effective. If say 8 people co-own a property, then you have a getaway for a week, or just a weekend/long weekend every couple months.
Alas with hard-sell timeshare you don't really own it. (if you did you could just collect all the other shares, and sell it as a house.) In this situation buying forever obligations seems like a bad idea.