Explain Homeowners Insurance

Explain Homeowners Insurance. If you got 4 quotes from 4 different insurance companies on a $200K house, the quotes would all be different. Why do smart people never let the insurance company charge them for insurance on the land?  Now, if you owe $180K on that $200K house then you have to carry 180K at least in insurance (you have to cover the mortgage on the home). But if the land is worth $30K and you only owe $100K then you should only buy $170K in insurance. Agree or disagree? (no right or wrong answer).