https://en.wikipedia.org/wiki/Human_jaw_shrinkage

The main contributing factor to the recent increase in malocclusion is widely considered to be due to a sharp reduction in chewing stress, especially during critical periods of craniofacial growth.[10][1] Experiments done on non-human subjects have shown that induced nasal blockages and/or dietary changes earlier in life lead to maladaptive morphological change in their jaws, intended to simulate what we are observing globally in human children.[4] Significant craniofacial changes due to diet have even been experimentally shown in pigs during development; researchers fed groups either a hard-consistency diet or a soft-consistency diet, for eight months in total.[11] Drastic differences in jaw and facial musculature, facial structure, and tooth-crowding were observed; researchers directly related the findings to what we are observing more in human populations.[11]

so too much damn baby food?