Techflex can Definitely make the cable less "flimsy." Although, I don't believe it will make them less prone to breakage (I've had issues where the cable meets the connector) unless you use heat-shrink tubing as suggested (over the connectors as well).
I'll try to attach a pic of a couple of cables that I covered with Techflex (Flexo PET) 1/8" in different colors. I finished one with heat-shrink (black) at each end of the Techflex, and the other has printed heat-shrink over the connectors.
1/8" Techflex Flexo PET fits easily over the small "Lightning" end of the USB-Lightning cable, but will not fit over the USB end, so if you're trying to cover a USB-30 Pin cable, it won't work.
Hope this helps.