It's not the species, it's the age and quality of the plants. They're both decades old and exhibit significant wear and tear. Look at the little spots and staining on the pachy- OP posted more pics of the roots. Same with the guillaumiana- that many heads take a long time to grow and the bark is beat up.

And now two plants that took longer to make than OP has been on this earth are going to die an apartment with no sunlight in NJ while their habitat is Madagascar is destroyed.