I think you're conflating two precepts. Just because you can write an exploit, it doesn't - inherently - mean that you have the skills/knowledge/tools of where to look for all signs of exploit having occurred on your device(s).

From the inference of that logic, every developer should be able to use gdb or Windbg to ascertain where they shot themselves in the foot - but we know that this specific set of skills isn't inherently required to be a developer.

So, the same logic would be true here: Just because you can write a hand full of exploits, it doesn't inherently mean that you have the tools/know-how to be able to ascertain if any of all of the available exploits in the wild (or in private, re: tools for Trenchat) have been used on your phone.

Edit: gbd != gdb