the big corporations that have a different field that has nothing to do with bitcoin will not be interested in it unless it becomes famous worldwide so they come in too.
but those corporations that are somehow related to financial things, are always interested in bitcoin and many of them have already invested in bitcoin.
This seems about right. Financial institutions etc are taking an interest as they should(bitcoin directly affects their business in a lot of cases) but for other big companies outside of this it'll only become a concern once bitcoin becomes a worldwide mainstay of commerce or business. Apple for example won't be interested in bitcoin clients/tech for their devices until it becomes big, like they didn't really care about credit cards until they got big and then they did Apple Pay.