LA has one-fifth the transit ridership per capita of Toronto. Toronto would do well to emulate them.
You're missing the point, as is everyone else trotting out ridership statistics.
Of course LA is going to have lower ridership statistics than Toronto. LA is the original decentralized city built for the car. It doesn't have a downtown with 400,000 jobs or 19th century neighbourhoods with 36,000 people/mi2. None of this, incidentally, is the job of transit planners or transit agencies, or, maybe even the work of planners. A lot of this is centuries-old development patterns that reinforced the way a city developed before it had a department of planning or before planning was taught at schools. If LA was located in the Northeast its ridership would be higher, even if it had fewer rapid transit lines or an apathetic transit agency (which many Northeastern cities do).
What matters is that LA is improving its transit service while the TTC has, until very recently, shuffled its feet. While we might joke about how LA only has 154,000 light rail riders, 25 years ago they had exactly zero rapid transit riders, while 25 years ago the TTC's ridership was comparable to what it is today.
The east vs west question is interesting. You don't hear much on the progressive transit front from cities like Jacksonville, Indianapolis, Quebec City, Raleigh, and so on (though perhaps there's projects I'm not aware of). Cities like Raleigh or Quebec would have the money and the political will to build mass or regional transit lines, cities like Indianapolis and Jacksonville have the spatial unity that plagues cities like Detroit and Atlanta. I assume it's largely due to a difference in municipal cultures between east and west...differing views of how a city should grow and evolve, differing levels of optimism and boosterism, etc.
I think that Western Canadian and American cities benefit from the following things wrt transit:
1. Metropolitan regions largely within the boundaries of one or two physically large counties. This allows for a regionally integrated transit system to naturally develop, avoiding fiefdoms of little, local transit operators.
2. Largely postwar development meant that cities could plan growth according to the postwar concept of comprehensive development. Planning was not really much of a field, outside of landscaping and design, before WW2.
3. No labour union-mafia-Democratic party machine nexus. Okay, this is sort of an American phenomenon, but it applies to an extent to cities like Montreal, if not Toronto. Back in the 1910s and 1920s, poor immigrant groups in the US climbed the social ladder by forming labour unions and organized crime syndicates and by electing members of their group to office through the Democratic party. While this certainly raised the standard of living of poor, landed immigrants, it also laid the foundation for massive corruption and appointments to key public sector positions based on nothing but patronage. Even though these groups don't really exist anymore, this managerial "style" and way of doing business persists in Eastern cities.
4. No old boys clubs. Similar to (3), only advocating for different groups in these same, eastern cities. Similar effects.
I should mention that it really depends on the time when the city was settled, rather than where it is on the continent. San Francisco suffers from a lot of (1), (2) and (3), probably because it is as old and established as cities on the Northeast. Not surprisingly, their municipal transit operator is godawful for all the reasons we've mentioned.