depends on what method you mean by "we" Do you mean agile methods are not working for your team or do you mean the old waterfall method is not working for you?
I think it doesn't matter to much what method you use just as long as you have excellent communication between client and the end development team.
Agile works well enough for our teams at work as long as everyone is aiming for the same goal. I used waterfall only once and it ended up a "failure" or a "qualified success" depending on your point of view. What we produced wasn't really what the users and customers needed or truly wanted even though it was to the spec that we all agreed to.
Think beyond agile and other current cutting edge methods. What I'm really asking about is will software development ever become so productive that significant, useful applications could be created for such a low cost that "throwaway" one-time development that occurs only to take advantage of fleeting opportunities or needs is fairly common and is not considered "extravagant" but rather a smart thing to do?
I think it doesn't matter to much what method you use just as long as you have excellent communication between client and the end development team.