Comparing DEN and MIA is like comparing beans and apple pie.
Yes DEN is a larger Star hub, however it's used for a completely different purpose than MIA.
DEN is a Domestic Gateway and East-West Connector. MIA is strictly a Latin & South American Gateway.
Not only that, but MIA is located on the East Coast, while DEN is in way inland really in the middle of nowhere. You simply cannot compare DEN's Germany service and MIA's Germany service.
It's good enough that DEN happens to have a Germany flight. It could have nothing.
Again, 2 completely different purposes for the 2 hubs.
MIA cannot touch DEN when it comes to domestic service and frequencies.
If DEN was on the East Coast, then things would be a lot different. DEN would have plenty of Europe service but it would not be a Domestic Gateway or East-West Connector like it is now. Physical Geography is a huge factor in the role of a hub.
If you want to compare MIA to something, compare it to IAD.
"Generosity is giving more than you can, and pride is taking less than you need." - Khalil Gibran