Keeping early game materials and phasing out late game.

Instead of getting rid of the dirt for making bricks and using limestone, don't know of any producer that produces bricks from straight limestone, should have stayed dirt and just naturally phases out as the demand goes up. Getting rid of the dirt makes me skeptical of the suggested change for taking iron production out of the game. This should not happen, just make it so the Tier 3 manufacturing can use steel instead of iron to produce tier 1 construction parts, just like it moves to steel to make the mechanical parts. Phasing things out of production makes this game feel better, instead of just taking out an entire production chain abruptly. Also, have solar, where is the wind power?