I don't think the problem with porting eManager to other systems lies with the browser or the OS.
The browser is just a front-end to an SQL database.
The OS is just the host of the same SQL database.

The database system is Microsoft's SQL Server and it is one of their crown jewels. There is NO WAY (imo) that Microsoft will EVER port their SQL structures to any other host OS. They provide connectivity to SQL Server from/to other systems, yes. But that's how far it's gonna go.

You can question their decision to go with SQL Server, but I don't think there is anything to be gained by that. They know that business case better than any of us.