> Cities like Shanghai and Bangkok are massively overcrowded and cars move like molasses – they’re just too big. Motorcycles are vastly more practical in these types of cities, especially for solo travelers.
Even more practical for most uses: A simple bicycle. If it's too hilly, an electric-assisted bicycle.
Doesn't use any gasoline and causes much fewer accidents because of their lower speed.

The Can-Am Spyder hasn't even been on the market that long and I see them everywhere in rural Pennsylvania. They aren't effective at lane splitting but with no real competition in the US their sales seem to be doing pretty well.
The Tricity is a different market but also less than a 3rd of the price. These are meant as city commuters but after seeing the bicycle the other day with 2 front wheels intended for sand etc. I can't help but wonder how well this setup would do off road. I think they would probably fare better in the rain too.
@Freyr bicycles are also kind of impractical means of travel for people who have commutes longer than 4 or 5 miles and they can be a nuisance for automobiles if in the road because they travel under the speed limit.

I disagree with the comment about the Cam Am Spyder not being a practical three wheeler. IMO, it is very practical. I also consider it be very nice looking.
I believe the tilting is only really need at higher speeds. At lower speeds - like driving in a city - it would not be really needed.

I admit I've only got 58 years of two wheeling behind me, but I'm currently riding my Honda Reflex 250cc in groups with several MP3 Piaggios. and I don't see any advantage to them at all except not having to put your foot down, a trivial non-problem for any low seat bike.
The front end is quite complex, the wheels are still small, and I wonder what the result of a flat in front at speed would be.
For absolute simplicity and economy, the 125cc low line bikes and scooters, like the Honda 150, seem the best idea. From there, it seems just personal esthetics and willingness to pull off sheet plastic Tupperware to get to anything.
I don't think the three wheelers are any safer.

Being retired, I no longer commute, but I do need to go into town quite often. Living out in the countryside causes me to need a vehicle that not only gets me into town, but allows me to shop there too. And having shopped, bring what I have bought back home. My dog's weekly food requirements alone would tax the load carrying capacity of nearly all of the vehicles discussed.
While I can understand the benefits of having the extra grip at the front end that the reverse trike arrangement delivers, I would still feel that the tilt mechanism would allow the thing to slide from under me before I could catch it if I hit a particularly slippery patch. At least with a car, I stand a chance of catching it before it falls over. Whilst being physically old, I am still young enough mentally (circa late teens, I reckon) to enjoy deliberately doing so when conditions allow - it provides one of the very few plusses from the winter's snow.
In short, you would not catch me on any tilting vehicle in winter conditions, or, if it doesn't have weather protection, even when it rains. In short, these vehicles are not really much of a traffic solution in countries that are far flung from the tropics, and not much use there either in the monsoon season.

Two wheels at the rear is not a good idea, except posibly when you have a burst or rapid puncture.
There are a large number of vehicles that demonstrate this, from the famous APE mini van to certain of Reliants "cars". The weight transfer on cornering needs increasing resistance to outwards tilt at the front which isn't easy to produce in the normal motorbike way unless the rear wheels give virtually zero resistance to falling over when stationary.

I will go with Piaggio ....... beautiful. Oh, I am sorry am I suppose to look at the vehicle?

i bought one of the first MP3's in Boston area...it is way above any two wheeler in terms of stability and cornering ability. The yamaha model is a knockoff for sure..nothing new there...but yamaha is a great company. i'd buy one... but i want the enclosure and 500cc....room for me and da Dog.
cheers,

The price is around $5,000 that not very "affordable",

I've ridden 2 wheelers (bicycles and motorcycles) for 40 years. I've lost traction with the front wheel on both and had the resulting road rash and emergency room visits. From what I read, the two wheels in the front design does a lot for stability in marginal situations and considering all the crap on the road in cities, that is a good thing. I'd love to ride an MP3 just to see what it's like. I have ridden a CanAm Spyder for a day and did not like it. My 2 wheeler sensibilities rioted in curves at speed and I did not enjoy the experience. The orange one in the picture above is not to my taste, but some other versions look much better in my eyes. The MPS looks a little insect-like in person, even with a beautiful woman astride it, but as with most vehicles, you really don't see much of them when you are going down the road. How it feels at that point is the important thing, not how it looks. When you get off and are admiring the thing, that's when it's looks matter.