No. This is not a trivial matter. The decline starts around the mid 20th century, is occurring globally, and levels have reduced by standard deviations from the old norm. Read up on it. It's way more serious than you think.
You're right, it isn't a trivial matter. However, neither has it been well explained. For example, how exactly has porn been ruled out? Porn also grew steadily since mid 20th C...
Correlation is not causation. Computing performance has also increased significantly since the mid 20th. Should we blame Intel for the drop in T levels? Where the hell do you get the idea that porn reduces testosterone? Research shows that watching porn increases testosterone levels in men https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2799222/