There might be some validity to this thinking:

(1) If you build part of it and show that it works, it makes it more of a concrete reality. Instead of asking people in urban areas to give up precious right-of-way to build something hypothetical, you're asking them to give it up to build something they can see.

(2) You're also asking the urban areas to wait less time between when they give up the right-of-way and when the system is built. By pushing the rural areas to the earlier part of the schedule, you can move the urban areas to the later part of it.

(3) If it's built in one part of the state, it creates peer pressure for other parts of the state to build it. It looks bad to be the one part of the state that is blocking it.

(4) While the sunk cost fallacy isn't rational, "we've spent this much and we're half done already" will still convince some people.

I'm not saying that overall this was a good strategy, but I can see some advantages. In any case, it seems like the main issue was massive cost overruns.