At some point Philza, Wilbur, Techno, and Tommy were traveling and Philza had to do something, so he asked Wilbur and Techno to look after tommy and make sure he doesn't wander off or something

Ofc, Wil and techno immediately got distracted immediately and boom, tommy was gone

Tommy found the dream smp in it's early days and dream let him live there for a few months, meanwhile Phil, Wilbur and Techno just kept searching for him everywhere else until they gave up (that is until wilbur moved into the dsmp and started L'Manberg)

There, a headcanon that satisfies both sides