Of course, this idea doesn't give credit to the inventors and benefits copycats. I just wanted to mention the idea.
Well, let's take medicine with its huge R&D upfront cost as an example. Of course, given the recipe, the ingredients and the neccessary equipment, anyone can produce a medicine for dead cheap compared to the inventor, as they don't have to invest in R&D beforehand while the original inventor has to recoup the R&D cost and therefore has to call a price with significant markup over the manufacturing cost.
If some other manufacturer finds a cheaper way to manufacture the same thing, they can get a patent on their improvement, and push for some licensing deal once they have that.
(This doesn't change the fact that the modern de facto practice of patents is pretty messed up. I'm just saying that there's a good idea behind it.)
IMO, fair competition comes into play after the inventor has developed their product into something ready for production, otherwise the incentive to invent will disappear. Whether they then deserve a temporary monopoly to recover their development costs is up for debate I guess, but I'm talking about shielding inventors from getting robbed of their ideas.
The lowest cost producer does indeed enjoy a market advantage in the market for manufacturing.