Oh boy did you just bring back some really bad memories! When I had my shop I was always working pay check to pay check working into the wee hours of the morning to get something out the next day. I did a Mazda RX7 in lacquer two stage. Went home to bed and when I went back it was cracked all to hell. What a HORRIBLE day in my life.
Yeah on the durability, my truck was painted with lacquer, 9 coats, Five then sand then four more. It was done in 1979 and has seen a garage about half of the time since. It is out behind my garage right now where it has been for last 10 years and the paint still looks damn good. There is NO failure what so ever! It is faded all to hell, but a quick polish and it would look like new again.
That is lacquer primer, and paint. With the way we talk about lacquer primers and paints you would think the stuff would be falling off on the ground and rust covering the truck. But it wasn't that bad, just in "comparison" to urthanes it's junk.