I am not sure if this is a fix. But I have been successful installing Revit 2019 with the 2019.1 update. From what I can tell it seems that the hot fixes 2019.01 and 2019.02 will not allow 2019.1 to be installed. So I have opted not to install the previous patches and only install 2019.1 which according to the documentation includes the previous updates.
So I followed the information on the page. See image also.
Revit Build Numbers
Revit 2019 Build Numbers
Now the other issue I had was a computer that had the old install. I found that if I ran the 2019.1 install I got a prompt to remove the 2019.1 installation. Weird but I accepted the uninstall and and ran the 2019.1 install again and it worked.
It was a pain I had to go through all these hoops but I was able to get it to work. So far so good.
Please let me know if this helps anyone.