Have you been cutting the wilted stems off at ground level.

Did you prune it when you planted it?

Often, they outgrow their root systems at first and then wilt, not from fungus but from not being able to support themselves with small root growth.

This is why when you hard prune them after wilting they often outgrow it because they put energy into roots not flowers.

It is very frustating though. Some won't do this at all.

It is the Type IIs that are prone to it.

Yes, I have been cutting it back each time. It came back so full and strong this year but I am growing tired of this and would like to replace it.

Will it be safe for me to plant another one in the same place? In other words, is it contagious or is it in the soil?

Yes, no and no.

Get a type III they don't wilt

Here is a link that might be useful: viticella group