I never said it can't be done. I said you aren't going to get the lifespan of a molded hinge out of it, by several orders of magnitude.

A molded hinge lasts millions of cycles.

I also said that you are not going to get that lifespan out of anything that requires a specific material other than flexible ones.

If you need to make something out of nylon, then you are stuck using nylon for the living hinge. If you print with a secondary material, then it is no longer a living hinge. By definition a living hinge is made with the same material as the rest of the part.

So it's all well and good to make toys with it, but if you need a working component that requires specific properties that the above mentioned polymer doesn't offer, then you need to print it with two materials, or live with the greatly reduced lifespan.