Diminishing returns.
A few years ago, when my junky old car finally crapped out for good, I went shopping for new one. I could not justify spending $15,000 or more on a new vehicle. That's why I have a fleet of 30 beat up Dodge Omnis instead. If I stall out somewhere, I just abandon the thing, take the plate home and stick it on one of the reserves.
No way in hell you're gonna catch me paying $4,000 for poon. The way I look at it, that's at least 8 Dodge Omnis right there. That's 2 months worth of transportation.