Isn't it unreasonable that the cost of starting a property company is entirely borne by the owner, but the profit belongs to the property owner?

Reasonable. Property companies are generally limited liability companies, and shareholders bear business risks to the extent of capital contribution. Property management generally adopts contract system, and the charging standard is fixed. You can't ask the owner for compensation because of the loss, and the loss should be borne by the shareholders themselves. The income generated by the construction unit, property service enterprise or other managers in the residential area by using the owner's part, after deducting reasonable expenses, shall be owned by the owner.