I agree that it is a good thing that they worded the marketing info on the package the way they did.
However, I think that the PDF's would be EASY as pie to take down in a heartbeat. If they ever really believed that 4e is the one and only, those PDF's would not have stayed on line. Period.
Oh, eh, thanks for the editing
BBQ and coffee...
What do you mean by "the one and only?" They'd have to be utter morons to believe that everyone is going to convert to 4E. There are people out there still playing every edition from OD&D onward. Wizards has said from the beginning that they know not everyone will be on board with 4E.
Providing the .PDFs, and marking certain products as "edition-independent," lets them pick up a little money from the hardcore fans of earlier editions who are simply never going to convert, without supporting those earlier editions to such an extent that they risk splitting the 4E customer base. It's a smart move.