I agree with the OP.
For years I've agonized over creative block about working at a subject or a project, which is always my goal. I think it is possible to get a good "single" but without a context or body of work to support them, they feel a bit powerless after a while.
Ive been taking a lot of pictures while I am traveling, and even the ones I like, 2 days later I no longer care about. The good thing is while taking these pictures is that I have noticed a pattern of subjects that I am drawn to...In this case everyday items that are covered in some way (under tarps, car covers, tents etc), which I will use as inspiration for a project when I get home.
The travel grab shots have served as a sketchbook for a larger art-piece, hopefully.