I think a lot of people fail to gain because they do not comprehend PE as a spiritual journey. It is esoteric. Medicine and science are useful for optimizing regimen but that only goes so far when considering the relationship between the Mind and the Phallus.
This is an ancient concept not to be disregarded.
They, Mind and Phallus (both as independent entities and in their coming together in relation) are not only tools of pleasure but also of power. They make change in the world.
For instance, let’s take a look at the taboo practice of Indian Shaman hanging weights from their phalluses. What interest would one have in simultaneously enhancing the Phallus and revoking the possibility of its sensation? Because it is a spiritual journey. Gaining power and appropriating it properly to create change in the world. To imitate the perfection of nature with the craft of ingenuity and reason.
Likewise, different individuals approach this journey, PE, with different agendas. Some want a larger phallus because they feel their current one is inferior - that is, their position in the world is inferior and they want more power. Others want a larger phallus because they are motivated by love, they wish to provide more pleasure to their lovers and themselves. And some because they seek enlightenment and view the extension of their phallus as an extension of their purpose.
It is almost absurd at face value, but I think that it pervades into the growth itself. It is not merely an act of force or violence against the phallus to make it grow so you can fuck things better. But it must also be understood as a meditative process in comprehending the relationships between the Mind and the sexual organs of the body.