Why is GainsWave not recommended for people with long-term ED?

It is true that GainsWave is not recommended for some patients with certain underlying conditions—those with a penile implant, advanced heart disease, or active prostate cancer, for example—however nerve damage alone does not disqualify you as a candidate for GAINSWave therapy. In fact, shock waves helps to rebuild nerves by putting just enough stress on the body to trigger a healing response and the growth of new cells. This can, in turn, make the penis more sensitive, as well as dissolve micro-plaque in the blood vessels for improved blood flow.
We invite you to read our blog post below for more information about shockwave therapy, as well as P-Shot therapy which can be an excellent alternative for some patients.

I think that is said because people with nerve damage probably need an implant as it is hard to regenerate nerves. But I think every situation is different and the degree of damage needs to be evaluated. Some benefit from combining with P-shot.