Sephiroth is partially a product of his time, sure, but I wouldn't say "people realized he was never that good" is the explanation for why people aren't getting invested in him now. I think that's a bit too reductive.
And there are a lot of very good video games out there that I will never play. FFXIV might be one of them. I'm okay with that.
https://imgur.com/WqDcNNq
https://imgur.com/89Z5jrB