Indeed. If $job is not willing to buy and hand me a "work phone" then they are out of luck, nothing for $job gets put onto my private phone. If they think they need this ability, then they also need to add a line item to their budgets for the cost of the phone and the service. And when faced with this alternative, they have not, so far, decided they want to pay for a phone.

If a device is owned by a corporate entity it becomes trivial for them to engage in wildly intrusive monitoring.

For example, if Apple can verify the device was purchased by a corporate entity and then enrolled in an mobile device management system, it will allow a lot of things that it won't allow on a personal device - things that can be used for monitoring.