I've seen this on the wiki and it wasn't until today I had an epiphany. The design we so often associate with human Sparda is in fact not him.
How? You may ask. Well, it's because the costume itself is called the "Legendary Dark knight".
Legendary Dark Knight? They're talking about Sparda of course! Well, no.
In the ending of Dmc1 Trish refers to Dante as "the Legendary Dark Knight, Dante" and in concept art for DMC1 Thos design is labeled as "Dante, several decades later". Meaning that this is in fact Dante NOT Sparda.
I think all of us are mistaken in saying this is Sparda. It's Dante, an older Dante.