What happens if you buy a device for an employee and they leave the job a month later?
The device is property of the company. It can go to someone who can use it. If no such employee exists the device can go to the issuer (or the employee who handles that stuff), who shall issue it to the next employee who asks for a device of that type.
I have been in a couple of different companies, and it always worked that way. Only once I have gotten a new computer when I started. And that was because they were expanding and there was no old computer available. Every other time it I got old equipment: a PC that was used by my predecessor, a phone that was used by someone who went on his pension. And that's fine.
I wouldn't want BYOD unless there is a good solution for erasing the company secrets on the device without erasing my own stuff. I would demand extra pay for BYOD because it means I have to buy stuff for it, and replace it once it breaks.