It may be not true right now amid difficulty in finding labour and materials. Much like cars, the value of a used home is proportional to the cost of building a new home. When new homes are difficult to acquire, cost of used homes go up. Used cars have also increased in value lately for the same reason. This is not typical, however. These are normally depreciating assets.

Under usual market conditions, houses are headed to being on the older side and reaching the end of their effective lifetime, leaving little value left in the structure. You can renovate a home to bring it back to new-like condition, which restores value to the structure, but that cost must be maintained in the equation.