Two entirely different children

I recently watched a family video from when Greyson was 3 1/2. During one clip, it is evening and Greyson is clearly tired. He is sitting in my lap on the floor in the kitchen of our rented house in NC, crying and talking at the same time, saying he's hungry and wants a sandwich but on DIFFERENT bread. I explain to him that we don't have different bread, he cries a little more, and then says "Give me a hug". We cuddle, and he settles down and eats a string cheese he's been holding. The entire scene lasts for maybe 2 minutes. If I remember correctly, this happened maybe twice a month, at most.

Cut to our lives today with another 3 1/2 year old. The above scene times 20 in intensity and length plays out almost daily and often multiple times a day, with no warning or rhyme or reason for whatever triggers the blow-ups. One day I do something and it's fine, the next day it's ALL WRONG and causes yelling and crying and gnashing of teeth. Reece turns 4 on Tuesday, and I am so hoping that a magical transformation will occur on or near that date, because I feel I'm aging years with every day! I am planning on videotaping the next meltdown so we can view it in another 5 years when we have some perspective and (hopefully) no more tantrums. And to show him why we can't pay for his college since all our money is going to keeping me comfortable at a mental institution.