Why are there so few singles-only lifestyle events?
Because the demographic asymmetries are sharp. The single-male/single-female ratio at most lifestyle events runs heavily toward men, and singles-only events without couples to anchor the social structure tend to magnify the asymmetry into uncomfortable territory. Most "singles-friendly" events instead admit singles alongside couples — couples set the social tone, single females are welcomed at high ratios, single males are vetted and capped. The pattern serves more guests well than a singles-only format would.