> This code is usually there for a reason and a unikernel will have to implement large swaths of this code anyway.

The largest part of a monolithic kernel today is devices drivers, by far.

> Networking isn't trivial and I don't think anyone will be reimplementing the TCP/IP, UDP/IP, ARP, DHCP and more stacks without breaking in a few bugs themselves.

Sure. And then more people will use those stacks, and they will get better. The more the merrier, we have too much of a software monoculture anyway.

> The only real advantage I see for unikernels is that because all the hard work is done by the hypervisor they don't have to bother implementing device drivers

This. People continually underestimate the amount of work required to support the hardware ecosystem. This is also why rump kernels (note, not the same term as the unikernel known as Rumprun) are such an achievement, also very much underappreciated.