Why do so many manufacturers have patent protection? For example ~ ~ computer ~ ~ TV ~ ~ washing powder ~ ~ bath milk ~ ~ there are too many brands of soap to understand ~!

General patents can only protect part of the technology inside, and few patents can protect the whole product. Moreover, technology can be said that many times all roads lead to Rome, and effects can be achieved through several methods, but some are shortcuts and some are detours.

Even if it is a monopoly, there is enforcement to prevent monopoly in the patent, and the patent can be implemented by others.

These examples you cited all belong to the former, that is, patents can only protect a certain part of the product or some key processes, but not the whole product.