Rising land prices make it impossible for hard-working families to buy homes. Land prices make it difficult for new businesses to be housed. Authorities cannot afford to build parks or public transportation systems.
Extreme examples include the indication that the cost of all real estate in Tokyo exceeds the cost of all real estate in the USA. That of Kanagawa prefecture (bordering Tokyo) is equivalent to the cost of all real estate in France, Germany, Italy and the UK.
A sudden decline in land prices would reduce the availability of investment funds.