The reason why Roshan reclaims Aegis

The whole concept around Roshan seems quite good and balanced, but so far there is no lore to back it up or make any sense out of it.

So what do you guys think about the following logic?

1. Roshan lives in another realm and can join the Dota realm through the Portals – he prefers being in one of the pits, so ideally he always wants to be in the Dota Realm
2. To be able to live in the Dota realm, Roshan needs the Aegis of the Immortal
3. If Roshan is slain, he doesnt die, but he doesnt have enough energy left to hold Aegis anymore and is forced to drop it and therefore leave the Dota Realm
4. After Roshan was able to recover in his own Realm, he is able to reclaim it from the Dota Realm and come back through the Portals
5. If a Hero picks up Aegis and dies, he gets sent to the graveyard -> but since the bearer of Aegis cant die, its power sends the bearer back to the living realm, while Aegis itself stays in the graveyard(from where Roshan reclaims it later on, after recovering)