Why should inventors get patents for their inventions?

Answer 1

Patent protection gives inventors a temporary monopoly, more or less as a reward for coming up with the idea, and as a period of exclusivity where they can recoup any investment made in the development of the idea.

Answer 2

A patent gives the designer/inventor exclusive rights to produce the item for a defined number of years. During that time no one else can make the item or use the design in another product without permission from the person who holds the patent rights, and who usually charges a fee for giving permission. Sometime the patent rights may be sold directly and completely. Then someone else has control of the design and the right to demand payment for its use, but the original designer/inventor has received a payment for selling those rights.