IMO the main reason the Vegas monorail failed is the routing. They're on the backside of the casinos. Why bother? Take a taxi to the front door.
I agree that the corridor was a huge mistake. They chose a monorail instead of a more traditional system because it's sleek and sexy. And then they hid it from public view by putting it behind a bunch of plain big-box structures and parking garages. As a result, it's out of sight and out of mind. Like everything in Vegas, there's a sense of novelty to a monorail, but when you put it in the least appealing place possible, you lose a lot of that
I understand the allure to the casinos of the additional foot traffic going through to get on board, but putting it in the back of the hotels made it fail because it essentially only serves one side of the street. Most of the stations are more than 0.25mi from Las Vegas Blvd, which is generally considered to be what people will willfully walk (0.25-0.5mi is the upper limit, which is why transit stations are typically ~0.75mi apart). By building it back there, they instantly lost the ridership of anybody who is originating or ending their trip on the west side of the street. Building it in the middle of the street (and possibly taking up some lanes for stations, and making street traffic worse in the process) would have allowed for a much higher ridership
And remember that this isn't your normal peaceful walk through your neighborhood to the local elementary school, it's a high-stimulation environment that's constantly trying to grab your attention; especially on vacation, people want the least-stressful option, and searching through a big casino for a monorail in the back isn't it
The Vegas monorail crossed a lot of different property lines in a very small area, it was bound to be a very difficult system to run.
This is going to be a problem anywhere with any transit system. To get to destinations, you need to cut through some existing areas, and people are going to be upset about it. It's not unique to Vegas in any way
Additionally, the parcels along the Strip are huge by any standard. For example, Planet Hollywood has about 0.15mi of streetfront, the Bellagio has about 0.25mi, and Caesars Palace has about 0.33mi. In most urban areas, you're looking at multiple property owners within each 0.1mi block
Looking at the alignment, what kills it isn't the number of properties, but how differently spaced the backs of the buildings are. As a result, it's constantly twisting and turning to match the existing structures. Had it been built along the street (like pretty much every other transit system ever created), it would have been able to take a more-or-less straight path, which leads to easier and higher-speed operations