In certain applications, like mobile cranes, reach stackers, demountable wheel rims are used. I request the forum members to enlighten me regarding the purpose, advantages of using such rims.
I think this has more to do with past history than anything else.
At one point in time, the hub and the rim were separate pieces and I think these types of vehicles - which tend to use fairly old tire technology - have just continued to use what they used before.
As an example, I will point to trucks where you can still get 20" wheels with split rings. I hope everyone knows by now that those can be pretty dangerous. I am surprised you can still buy them.
One other consideration is weight. It is sometimes better to have several lighter components, than one integrated, but heavy component.