Do you think that my upper and lower dental arches are extremely underdeveloped? (Photos)

Look into Epigenetic Orthopedics with the DNA appliance to grow larger jaws and a better airway.  
Small jaws are due to improper developmet when growing due to allergies, tongue habits, tonsils and adenoids, not being breasfed and other environmental causes.
Growth will give lifetime airway benefits and create a full wide healthy smile.a L Shapira DDS, D,ABDSM, D,AAPM, FICCMOPast Chair, Alliance of TMD OrganizationsDiplomat,  Academy of Integrative Pain ManagementDiplomate, American Board of Dental Sleep MedicineDiplomate, American Board Sleep and BreathingRegent & Fellow, International College of CranioMandibular OrthopedicsBoard Eligible, American Academy of CranioFacial PainDental Section Editor, Sleep & Health JournalMember Cranio Editorial Board, Journal of Craniomandibular and Sleep PracticeMember, American Equilibration SocietyMember, Academy of Applied Myofunctional SciencesMember, Academy of Cosmetic DentistryLife Member, American Dental Association

The word "underdevelopment" has no meaning in orthodontics.  Orthodontic terminology is very specific and usually compares the size of the upper and lower jaw, or the size of the teeth relative to the size of the jaw.  If a person is short, you could refer to him as "underdeveloped".  Is this good or bad?  Bad if you want to dunk a basketball, good if you want to ride race horses.  I would be surprised to hear an orthodontic specialist use the word underdeveloped.  If you are not being treated by a specialist and are unhappy or confused by your treatment I would suggest that you find an actual orthodontist to properly explain and treat you.  If you are seeing an orthodontic specialist and are unhappy, ask for a consultation.  If you do not regain confidence in your provider, switch providers.