Because those big businesses are only motivated by the profit possibilities.
If you take away that protection then they’ll just stop trying. They don’t give a shit about any of the motivations you listed. They’ll wait for you to come up with something new, then use the advantage of their size to force you out of the market. You’ll end up either giving up or trying again at which point they’ll just repeat the cycle.
And there’s nothing you can do to stop them because now they can be as open and blatant as they want with directly using your exact plans.
And you’re going to compete with them on price then? Even when they can and will sell every unit at a loss until you’re driven out of the market. Unless you’re wealthy enough to be part of the good ol boys club, you can’t afford to play that kind of game. They can.