Not entirely. There are men who suffer from erectile dysfunction due to other identifiable causes. For example, men who take antidepressants known as serotonin-specific reuptake inhibitors develop difficulty in having orgasms, and this can lead to a psychologically-based inability to get an erection in the first place.
In most cases, erectile dysfunction is a blood flow issue. This is not to say that psychological factors have no bearing on sexual performance. But it means that men who in previous generations may have been reluctant to bring up the issue of erection problems with their doctors due to fear of being labeled “neurotic” can broach the topic knowing that most doctors today see erectile dysfunction as the physical problem it is and address it accordingly.