The Pedersen device was the product of Allied frustration and a theory of attack called "marching fire", a way seemingly contrived by generals to get as many of their own men killed as possible.
The idea was that soldiers would walk toward the enemy line, firing as they went "to keep their heads down" then shoot the enemy soldiers as they huddled in the trench.
It was a bad idea to begin with in the days of muzzle loading muskets; it was insane in an era of belt-fed machineguns. First, the enemy was well dug in, behind Maxim guns, and walking infantry was what we now call "a target rich environment." Second, the Pedersen device made the insanity even nuttier. An enemy might duck if he knows he is being shot at; but with the low noise and sub-sonic bullet of the PD, added to the noise of battle, the enemy would not even know anyone was firing at him. He would just continue feeding fresh belts into his MG.08 and mowing down the lines of attackers.
The solution ended up being the tank, plus the fact that German morale broke when the equally worn-out Allied forces were bolstered by fresh American troops.
It is unfortunate that more PD's were not saved; I would love to have one. But as a military weapon, the scrap heap was the proper place.
Jim