Except most state/local governments do have property taxes on houses, land, and cars. Not unrealistic to apply the same towards other assets. Specially since taxing homes and cars is counterintuitive because you’re taxing necessities, while taxing monetary/investment assets like stocks would make more sense to encourage more spending instead of just hoarding the money.
I think the joke is if there were more autistic people in charge of those things, the accidents wouldn’t happen