When I saw how the Las Vegas Monorail was implemented, it was pretty easy to predict what would happen.
It's off the strip. To get to it, you have to walk through the casino, and a casino's layout is designed to keep you from leaving without being impeded or distracted.
It doesn't stop at every casino. If you aren't staying at a casino with a monorail stop, you have to walk out to the strip and then back in again (see above).
It actually diverges from the northern part of the strip so that it can stop at the city convention center next to the Hilton. That made it that much harder to redevelop that part of the strip.
It doesn't (yet) go to the airport. If that extension is implemented, it might be useful. But at the moment, it's not very useful for commuting up and down the strip. There are city-operated shuttles that work better.
To those points add that it’s damned expensive.