This is how the Prestige mechanic works. It resets your progress at each new level (sawmill) but gives you a higher income multiplier and more opportunities.
You keep diamonds, reputation, biz points, chests, managers cards, and your Workshop. Based on your previous experience and the new managers, you might develop your new sawmill differently.
You keep diamonds, reputation, biz points, chests, managers cards, and your Workshop. Based on your previous experience and the new managers, you might develop your new sawmill differently.
Please note that you can't come back!