I cannot for the life of me figure out why they would not have simply cast bricks with an inflated balloon or plastic bag inside? They could even still do the i

I cannot for the life of me figure out why they would not have simply cast bricks with an inflated balloon or plastic bag inside? They could even still do the inside/outside resonator combo which is a neat trick too. I laughed out loud when they were using the big robot arm to do the texturing. Use your friggin hands.