Ok, agreed, a lot more plastic than metal these days.
My point evolves from my experience owning since '82 a Mazda RX-7 which has no grill at all on the front. It is more slopped than the Model 3 such that there is more of a glancing impact by gravel. I got all the paint protection I could get at the time on that paint but it was worthless pretty much in terms of preventing chips. And I understand that paint has improved a lot since '82.
When it is paint vs gravel at high speeds the paint mostly loses. These modern PPFs are multi-layer and clearly under development. Modern EVs will last more years than ICE vehicles so there is going to be more exposure and challenges for the surface coating whether on metal or plastic.
Repainting is an valid option at a similar cost. PPFs are likely to go down in cost over time and have additional features added.
I wish we could get PPF from the factory but painting is much faster generally so that is what we get until the "flufferbot" technology can be used to apply PPF.
Around here there is gravel on the roads from growing potholes and rock salt as well as all sorts of chunks of cars falling off. Until I can get the deflector shields installed, my poor Model 3 paint is naked without a little PPF to divert the incoming insults of modern life in the fast lane.