Arguing the other side for both you and the user above:

As shitty as the average driver is, I see a lot more car accidents in a parking lot than I see car accidents in some random field.

People hit the street lamps in parking lots, too. We mitigated this by using a concrete base that goes up a few feet. They can hit it but the lamps are still fine.

When you put the panels where cars are supposed to be, you have to put them up higher, this requires more material for the structure. Because the structure is now much taller, you need more material to keep it rigid.

That's true but solar panels aren't that heavy.

You'll also have a bigger profile compared to the wind, so you guessed it, more material is needed to make it stronger.

Wind isn't really that much of an issue due to the profile of the panels.

Oh, and if a panel falls on someone's car and damages it, or injured a person waking underneath, you'll get sued, so you need a wider safety margin, which means a stronger structure, which means more material is needed.

You can say that about almost anything. Have you not wondered how they can build large stores and warehouses so quickly? Solar panels are much lighter than their roofs.

When it rains on those panels, they create a concentrated line of water falling from a pretty good height. This will increase erosion of the parking lot, which means you need to do more frequent repairs to the surface, or you need to use more material to create gutters and channels to safely move that water away. If you go that route then you need to clean and maintain those gutters

Gutters and channels are rather cheap, especially compared to pretty much everything else in the project or even the cost of the parking lot. You can also save a bit of money by just angling the panels a bit and including a small space between them.

You're also going to have a large energized transmission network running over an area with extremely high foot and vehicle traffic

Solar panels are low voltage, around 40v. Electrocution risk is lower than with the street lamps.

that's not going to be a problem because the entire electrical system is going to be ripped out by a junkie before there's a chance for anyone to get hurt...

What's stopping them now? There's lots of copper in the street lamps and various equipment at a store. The answer is that the copper isn't easy to access. It would take someone way too much time to get any substantial amount of copper from the wires so long as the run back is protected. They would need to rip apart each panel to get to it.

Then there's also the additional complexity required to clean elevated panels like that, the difficulty in maintenance, complication to firefighting, the list of logistical issues goes on.

Not really - you just need a ladder.