The GATF with the kid by it is just a hair under 4' (hell the tank is 10x4x4) and the tanzaniae in the last pic was said by Wes, aka fugupuff, to be over 30". I consider anything Wes claims to be good as gold.
The problem with African tigers is that most people only have them for less than five years for whatever reason. Death, selling, moving, whatever. Most people don't have them long enough to let them grow out. The old females you posted are likely over 20 years old. If someone manages to keep an ATF alive that long, there's no doubt in my mind we'll see fish of that size. When was the last time you heard of anyone keeping any fish for 20 years?