Many of the native trees, shrubs, and ground covers sold now are male clones. In every place there are prevailing winds. The breeze generally blows mostly from one direction. Many landscapes are so plugged up, so crowded, that the breeze simply can't penetrate the mess. A landscape with no air flow is one where molds will thrive.
Molds grow best in conditions with poor air circulation.
If your own yards are over-grown and choked for lack of fresh air, then get out the pruning saw and start thinning them out. Clean, fresh air, free to move about, equals less mold and fewer mold spores. Sunlight and Molds Bright light and fresh air are the enemies of mold. Many landscapes have huge trees overhead that let in little light. Consider hiring a tree trimmer to thin out some of the branches overhead.