Absolutely right. TBM tunnelling is one of the techniques but it is not the only tunnelling technique. It is not one size fits all solution.
Sorry I replied at the wrong place. I repeat here:
You are right. Cost is not the only reason why you may want to go for non-TBM tunnelling. As you have pointed out there are some other important considerations in favour of conventional tunnelling.
Absolutely right. TBM tunnelling is one of the techniques but it is not the only tunnelling technique. It is not one size fits all solution.