As we know, many cities have not seen their transit ridership levels rebound to pre-pandemic levels (2019). This is true in the San Francisco Bay Area, where ridership levels are hovering around 70%. But it is not true in Paris, where things have more or less returned to where they were, albeit with a different demand profile throughout the week.
As far as I can tell, the determining factor seems to be whether a city has a network designed for 9-5 commuting or whether the entire city is generally oriented around transit. If a city is in the latter camp, demand has naturally proven to be more resilient.
It is tempting to want to use 2019 as the benchmark for comparison, but Jarrett Walker makes a good point in this recent post: "When are we going to stop describing our ridership as a percentage of pre-COVID?" His point is that our cities have permanently changed, and so it's time to set goals and benchmarks based on today's reality.
Many transit networks, particularly in North America, were designed to concentrate peak demand into a singular central business district. That is not happening in the same way anymore, and we are seeing an increase in new riders at different times. For example, Walker also points out that a number of transit agencies have seen weekend ridership exceed 2019 levels.
I have argued before that cities like Toronto are starting to plan for a post-car future. This is the only way we know how to solve traffic congestion, but it requires new land use patterns and a grid transit network, as opposed to a CBD funnel. In assessing their performance, cities will need to decide if this is their goal, or if they're content to focus on the past.