The land value tax isn't the problem here. We can discourage development through zoning, environmental policy, etc. In the absence of explicit restrictions, the

The land value tax isn't the problem here. We can discourage development through zoning, environmental policy, etc. In the absence of explicit restrictions, the market value of coastal land will reflect its potential for development, so landowners are incentivized to sell to developers even without a land value tax. As you say, this is a trend that's already occurring. If we want to reverse that trend and preserve coastal land, then we should take steps to explicitly protect it, not just rely on current landowners to resist development when doing so goes against their own economic incentives. In the case where society does take action to restrict development, then a land value tax does the right thing: the market value of the property falls since there's no potential for development, and the land value taxes owed are relatively small.