The auto market is a trillion dollars, compared to the 8 trillion dollar housing market... but cars go down in value while houses go up.
They also don't last 50+ years either, have land underneath them, etc. Once their value is used up, they're worth about $200 for scrap and that's it.
Now, cars can be an investment, but we're talking about ultra rare concours quality cars and such. Or limited production supecars. Though I wonder if that's all less about the cars and more rich people's ways of creatively investing money. I mean, me? Why buy a car I'm not gonna drive and enjoy.