IANAL but my understanding is that patents cover the implementation not the idea. If you aren't capable of practicing (yielding the product), you probably shouldn't be holding/filing a patent.
Let's say you invent a doodad in your garage. You have the implementation, you have a working device, but you don't (yet) have a product you can sell. You are unlikely to be setup to manufacturer this, so you'll you need to find a partner to produce that doodad. Patents protect you during this process, so that a manufacturer can't just go "oh cool we'll not pay you and instead just go do this under our house brand without you"
At least that's the theory. The reality is it's increasingly unlikely you'll be able to invent anything physical by yourself in a garage anymore in the first place and things like software have no barrier to mass distribution like physical goods do.
