Another Greek ephebophile issue.
The high point of Greek culture and art coincided exactly with the maximum popularity of ephebophilia.
Which makes it pretty unlikely their addiction to homo sex caused their eventual collapse.
The common conservative belief that Greek/Roman homosex caused their societies to collapse does not, unfortunately, fit the timeline.
The attraction to young men did not "cause" a demographic death spiral of the type Mark Steyn laments in America Alone (a possible "cause/effect") but it might have "caused" God to get pissed at their culture and arrange for them to get their ass kicked.
(E.g. think of Old Testament judgements, there was often a time lag baked in. cf Jeremiah 44.)
Cheers!