Self-fulfilling prophecy. So long as Manufacturers offered wagons, people actually bought more of them. It’s a well known issue. If they aren’t available on the lot to be bought, then of course they won’t sell any.
The problem with this and the story of “these cars don’t sell, so we don’t offer them” business from manufacturers is that they are beholden to share holders. If they don’t show that a product is not only profitable, but also GROWING year after year, quarter after quarter, then they are seen as a failure regardless of profit. This is not specific to the auto industry and you can see this in other industries.
The cars were always profitable, they just didn’t see the unsustainable growth that SUVs/Crossovers/Pickups are enjoying right now. So what should manufacturers do? Why, limit their portfolio to trucks only, of course!