TL;DR:
The steepest tramway with only wheel/rail adhesion was in Montreal (14%), which the replacement buses could not manage in winter.
For reference, this is what a 14% incline looks like. Nothing to sneeze at, note the drastic slowdown and the change in engine sound of the truck.
Now we shall replace or add to every street Monorails or what, good luck with that. Some streets are also so tight, a Tram or Monorail never fit trough such tight streets or the corner radius simply does not allow it. We have such Monorails here in Munich, we call them Tram, but they are only used in bigger roads without gradient.
Also, what Winter, it is Jan. here with Minus 1 C here. Hardly any snow can last long with such high temperatures. That maybe works in California, who already got some infrastructure or Russia, but for the rest of the world this is pointless.
Again, this is all not news and well-known, but not practical. You already got good winter care in the cities, which doing a good job cleaning the streets.
Some people just post random stuff, think that helps, it does not. Practical wise this is a nightmare, you need big streets, the infrastructure and the maintenance for such a Monorail is also a nightmare because you need lots of money + the graffiti factor, which means you need a bigger hall to protect such Trains or Trams - call them what you want.
A cheaper solution is to keep on using busses and use some more money for winter maintenance instead of building an entire new infrastructure for Trams.
Monorail is a train on one single rail.
This is a tram, trams are good.
That does not change much, you still need the infrastructure.
Some streets are also so tight, a Tram or Monorail never fit trough such tight streets
but busses do?
Some busses have in the middle a more flexible connection, which allows them to get considerable tight corners.
