According to whom? What's the source of your statistic? Because it sounds astonishingly high, for me to get erections and then lose them. If what you are talking about is men not being able to get erections, why don't you be honest and say that normally this is completely associated with age (say, over-60, and especially over 75), and that the Viagra-class of medications is the simplest and easiest response.
Arterial vascular diseases account for nearly half of all cases of ED in men older than 50 years of age. Arterial vascular disease includes atherosclerosis (fatty deposits on the walls of arteries, also called hardening of the arteries), which may affect the heart (history of heart attacks, angina, coronary artery disease, myocardial infarct) or blood vessels in the legs, peripheral vascular disease (problems with blood circulation to the legs), as well as other areas of the body including blood vessels supplying blood to the penis and high blood pressure. Prolonged tobacco use (smoking) is considered an important risk factor for ED because it is associated with poor circulation and reduced blood flow in the penis. This is related to microvascular damage (stiffening of the artery as well as smaller caliber vessel size secondary to endovascular atherosclerotic plaques).
The diagnosis of erectile dysfunction relies on the history. It is important to ensure that the problem is truly erectile dysfunction and not a different type of sexual dysfunction. The evaluation of erectile dysfunction focuses on identifying possible medical causes of the erectile dysfunction. Thus, the physician should conduct a full medical history (reviewing past medical and surgical history, medications, and social history) as well as physical examination. Thereafter, a more focused and thorough sexual, medical, and psychosocial history should be performed. Erectile dysfunction is a delicate topic, and a doctor should be sensitive and caring to make you comfortable about sharing these intimate details of your private life. Prior to your visit, you may also complete a validated ED questionnaire such as the IIEF-SHIM questionnaire.
Trauma to the pelvic blood vessels or nerves can also lead result in ED. Bicycle riding for long periods has been implicated as an etiologic factor; direct compression of the perineum by the bicycle seat may cause vascular and nerve injury.  On the other hand, bicycling for less than 3 hours per week may be somewhat protective against ED.  Some of the newer bicycle seats have been designed to diminish pressure on the perineum. [37, 38]
If PDE-5 inhibitors are not suitable or don’t work, other therapies include injections into the base of the penis, which cause flow of blood into the penis and a fairly immediate erection that lasts around an hour. The drugs injected are alprostadil (Caverject and Erectile dysfunctionex) and Invicorp (VIP and phentolamine). Alprostadil may also be inserted as a gel into the opening of the penis. This is not suitable if your partner is pregnant.
Penile erection is managed by two mechanisms: the reflex erection, which is achieved by directly touching the penile shaft, and the psychogenic erection, which is achieved by erotic or emotional stimuli. The former uses the peripheral nerves and the lower parts of the spinal cord, whereas the latter uses the limbic system of the brain. In both cases, an intact neural system is required for a successful and complete erection. Stimulation of the penile shaft by the nervous system leads to the secretion of nitric oxide (NO), which causes the relaxation of smooth muscles of corpora cavernosa (the main erectile tissue of penis), and subsequently penile erection. Additionally, adequate levels of testosterone (produced by the testes) and an intact pituitary gland are required for the development of a healthy erectile system. As can be understood from the mechanisms of a normal erection, impotence may develop due to hormonal deficiency, disorders of the neural system, lack of adequate penile blood supply or psychological problems. Spinal cord injury causes sexual dysfunction including ED. Restriction of blood flow can arise from impaired endothelial function due to the usual causes associated with coronary artery disease, but can also be caused by prolonged exposure to bright light.
If you’re experiencing psychological ED, you may benefit from talk therapy. Therapy can help you manage your mental health. You’ll likely work with your therapist over several sessions, and your therapist will address things like major stress or anxiety factors, feelings around sex, or subconscious conflicts that could be affecting your sexual well-being.
Alprostadil is injected into the side of penis with a very fine needle. It's of great value to have the first shot in the doctor's office before doing this on your own. Self-injection lessons should be given in your doctor's office by an experienced professional. The success rate for getting an erection firm enough to have sex is as high as 85% with this treatment. Many men who do not respond to oral PDE5 inhibitors can be ‘rescued' with ICI.