[Haskell-cafe] What happens if you get hit by a bus?

[Michael Litchard]

I'm learning what it means to be a professional Haskell programmer,
and contemplating taking on side jobs. The path of least resistance
seems to be web applications, as that is what I do at work. I've been
investigating what some web developers have to say about their trade.
One article addresses the question above. His answer was that he uses
RoR which has a large community and he is therefore easily
replaceable. My question, for freelancers in general, and web
developers in particular is this: How do you address this question?  I
imagine potential clients would need to be assuaged of their fears
that hiring me would lead to a lock-in situation at best, and no one
to maintain a code base at worst. Lock-in won't be part of my business
model, also sooner or later we part ways with the client. When the
client wonders, "What happens then?", what is a good answer?