Sprint has to account for where people are most of the time and how many people will benefit when it prioritizes network improvements.
There's only so much funding and it has to maximize ROI on its build.
I agree, having continuous LTE between Los Angeles to Las Vegas makes sense to have. However, the number of people who will actually benefit is greater if Sprint prioritizes investing in Los Angeles and Las Vegas. I think that's Marcelo's thinking on this. The build between Los Angeles and Las Vegas will come in time.
Finally, as far as Network Metrics go, RootMetrics tests metropolitan markets, not the highways between them. If Sprint wants to show progress on these numbers/awards, it has to focus investments in the metro markets themselves, not on the highways between them.