It's under development close to 4 years. If the person has time (or doing Ph.D. or something on the subject), this is a very viable time frame to do all of this.

There are other people's work in it, but it's a one man show mainly.

This is a passion project and it shows.

Edit: Plus, this is the second iteration of the hardware. First iteration is at https://github.com/jankae/VNA