#2 - to keep the size of the board the same, and not use as many chips (RAM, I/O, etc.) kept the costs down for the LC 475.
If you compare the LC 475 board to the Quadra 700 or 800, you can see those other boards are much bigger and prone to Cap Goo Trace Rot death than the 475. It is more data lines that can be killed, and more chips to support the wider bus.
With fewer chips and lesser data lines for a smaller board, the cost of LC 475 was kept to a minimum.
If you compare the LC 475 board to the Quadra 700 or 800, you can see those other boards are much bigger and prone to Cap Goo Trace Rot death than the 475. It is more data lines that can be killed, and more chips to support the wider bus.
With fewer chips and lesser data lines for a smaller board, the cost of LC 475 was kept to a minimum.