Scalability is the most critical point for adoption by corporations because they have to think about tomorrow. A lot of people who are just private investors in bitcoin are calling for massive adoption by the whole world and yet they don't consider the issue of scalability. Sure, you can use it to send your uncle money for the fuel he just put in your car, but can corporations adopt a blockchain ledger or code an algorithm to make it work for a long enough time frame to make it profitable for their needs?

Maybe not at the moment, but they'll figure out ways to do it soon.