It's still a team sport. The Leverkusen team was a well rounded machine far ahead of de Bruyne's Wolfsburg team. Take de Bruyne and Wirtz out of both teams and Leverkusen is still the far better team.
Yep I took a look at that Wolfsburg team:
It's incredibly lopsided and unbalanced
A midfield of Luiz Gustavo (Good player), De Bruyne (Excellent), Perisic (at the time hadn't developed), Vierinha (who?) and Maximilian Arnold (decent)
In defense, some okay players like Naldo, some guys I've never heard of.
But then upfront, a strike Partnership of Andre Schurrle, Bas Dost (

) and Bendtner (

), Bas Dost scored 16 goals, Schurrle scored 1 and Bendtner grabbed a few.
Meanwhile that Leverkusen team had Wirtz, Frimpong, Grimaldo, Boniface, Tah, Xhaka, Andrich, Hincapie, Hoffmann.
Like overall, that Leverkusen team is a level above so De Bruyne's success or lack thereof compared to Wirtz is not a fair comparison.