Some others have already stated this, but I’d like to reiterate it. If a man can attract women without attending a singles event, there’s no reason for him to go to one. That, I believe, is the basic answer to the women’s question: why don’t the men they’re interested in attend these events?
As for the men they’re not interested in, they tend to serve only as an ego boost—at best—for the women present, without any real matches being made. The internet has pulled back the curtain and revealed truths to men that, in the past, they might never have known.
Since women often encourage each other not to adjust standards that far exceed their actual value in the dating market, these events will likely remain ineffective for the foreseeable future.