I actually own Topogun 2 and 3, and know the maker. I don't have a problem with the software, but I agree with you. 3DCoat is my go to software for retopology, and a bunch of other things. Blender does have Retopofolow, which is pretty good (and free if you download it yourself from Github if I recall),
I'm not sure if it's made to gatekeep or anything like that, it's actually cheaper then buying 3DCoat outright. Though I like the software, I just think 3DCoat has a far better Retopo and UV suite.