If those trees were pollarded annually, the cut areas would NOT look like that. There would be big knobs of old growth at the trimming sites. Not seeing any of that here. The way those trees were topped (not pollarded, which is a very careful process that has to begin when the tree is immature) is excellent way to kill them due to loss of hydration, open sites to infection and parasitism during the best time of year for both, lack of nutrition due to so little greenery and new budding growth being left, sunburn and other exposure damage, and a myriad of other possibilities. Plus, if they were topped annually, they would not have the lovely drooping branches seen in the other picture but would have tons of vertical suckers instead.
This is what an annually pollarded mature tree should look like:
If this was done by the city, the public works arborists should be protesting in front of city hall and screaming their heads off right now. I'm not hearing about that, so... Tree law!