No every innovation can be materialized just by a handful of people like a software app, and not everyone who is involved in this process is your buddy and can be assumed to have good will.

In any hardware-related industry, you will need corporations to mass produce your innovations. If there is no patent system, the moment the manufacturer figures out how to produce it, the innovation is no longer yours. In fact, this is one of the major reasons there is this whole US-China trade war in the first place. Basically, local Chinese contract manufacturers have access to the manufacturing procedures of foreign companies who invent the products, so they just directly copy it and undercut their customers.

Patent also protects the interest of individual researchers who do RD for corporations. But that’s another topic.