I don't think $100bn is reasonable - that's a million cars! There are only 13k taxi medallions in NYC, which is a good point of reference as the limited supply

I don't think $100bn is reasonable - that's a million cars! There are only 13k taxi medallions in NYC, which is a good point of reference as the limited supply means they are efficiently utilized. Extrapolating that out to the general US population yields just over 500k taxis, and that's to completely replace every single taxi in the country.