I had a bad fan & took it apart, thinking I might claim the ring magnet (it's pretty strong). I was impressed at the complexity of the assembly.
Also you can see, the PCB is actually a formed plastic shape with various formed features and normal traces on the bottom. Also note under the DIP IC, that there is a PCB molded support to position the chip exactly. A LOT of thought went into this "pcb". I suppose you can spare no expense when making fans by the hundreds (of thousands).
I was quite impressed & somewhat surprised to see that there is a factory cable connector on the pcb (rather than using soldered wires, to save more pennies). The two-wire mate is in the 2nd photo.
Notice also, in the connector area, the board is stepped down (thinner). This does NOT appear to be any sort of sandwich construction...the board is one piece.
The discontinued chip is interesting---it contains the hall sense & other driver & some protection goodies (the rest of the pcb has three parts: 1A diode, a resistor, and a 1N4746)