What should drive the decision behind doing development upon one or more than one framework?

For instance, an ERP is (mostly) run on a Windows station. It leverages full access to device's resources, like printers, barcode readers, fingerprint readers and the like. It's usually more responsive and easier do develop with.

That being said, some parts of it must be accessed exclusively in self-service mode, by enterprise's customers, suppliers and partners. This could be accomplished with smartphones, tablets, or even desktops running a web browser.

What are the economics behind that? Should two team be kept, each one doing work upon its own framework? Or the most permissive framework should be chosen? Should I care something other than HTML technologies? Should I consider native technology for each device?