There are two attractors, it could push people to do it themselves but I think it's more likely that it evolves in stake pooling. Stake pooling in pure PoS involving trusting the pool operator to a great deal and I'm concerned it degenerates to a very centralized system. Adding optional delegation is a safety valve that takes this into consideration.

What Tezos does is merely let you lose a different key to custody funds and to create blocks. By itself this creates the possibility of delegation.

Last but not least, with trusted hardware the difference blurs even more.