First of all "куда деваться?" is a question.
Literal translations is something like "Where can we go?" or "Do we have place to go to/hide in?". In fact it is idom with meaning: "Do we have options to choose from?".
There can be statements: "некуда деваться", "деваться некуда", "никуда не деться" and so on.
So, "А куда деваться?" is "But do we have options to choose from? ('but' implies answer 'no')".
"надо идти за спросом" - "we have to follow demands (of clients)" - it's just statement of first law of free market.