Revert "Remove "New" prefix on economy-related API."

This reverts commit 79ce0c75561b8a5b579653044f9b0659f3e725c1.
Revert "Implement (mostly) new economy system"

This reverts commit 76e0168d2e1d1a2e28cc53d54e9a37523e4f7cf3.
Correctly implement new economy system
Remove "New" prefix on economy classes