I'm not sure about the whole "there's enough work". And even if there's enough work now it will get slimmer and slimmer due to the whole self-organised aspect and other Agile consulting organisations.
I understand your fear, and maybe now you can understand the fear of your client's employees when you introduce change. For instance the guys from the Project Management Office, when you say: There is no such thing as a Project Manager in SCRUM.
The only thing that helps these guys and you is the following:
1 Do an excellent job (even if this means making yourself redundant)
2 Stay one step ahead in knowledge and skills
3 Communicate about 1 and 2, so people know who you are and what you are capable of
If you follow this, there will always be more than enough jobs for you.