Thought: in lore, c!Tommy grew up an orphaned street kid.
Evidence:
He's made multiple comments about raising himself. Wilbur seems to have been the one who looked after him the most ("Will you still look after me when I'm alone?" "I named... Tommy," etc.);
He consistently rejects nice housing: choosing to sleep in a tent in Logstedshire instead of the nice place Ghostbur built for him, sleeping in a dirty hole even after Techno found him under his house, inviting Tubbo to move in with him in his dirt hut instead of both of them living in Snowchester, etc., as if living in an actual, nice house is an alien/uncomfortable concept to him;
In general likes using poor materials (like cobblestone) for building;
He prefers thievery and scamming over getting things legitimately, maybe cause the former way was easier and more reliable/safer growing up;
Perhaps he clings to sentimental items because he had so little growing up as is, which is why his ender chest is filled with those special items instead of actually useful stuff;
Items that are not sentimental he uses up flippantly cause on the streets he had to use whatever he had to survive;
He canonically knows how to sew and patch up his own clothes, which would be necessary if new clothes are hard to come by;
If we want to go full lore mode, Wilbur building L'manburg to escape those conditions and find Tommy an actual home.
shout out to the doctor who looked at my physical results and said 'you will live to 100!' and then looked at my mental health results and said '...if you want to'