But except for the crooks and malcontents the citizenry as a whole certainly didn't look ready and willing to rise up and turn everything upside down.
Well saying "except for the malcontents" is a meaningless statement; by that definition, anyone who thinks there is a problem is a "malcontent" and therefore can be ignored.
And your statement is questionable. Clearly most Gothamites didn't seem to believe that a violent revolt was the solution -- but we saw from scenes at the orphanage (where even kids were talking about needing to run away and join an underground economy just to find work), and from Selina's statements about the desperation that drove her to take a job from Bane's group, that there were some very, very serious problems with wealth inequality that were hurting most Gothamites.
The two scenes you cite aren't enough to justify the uprising. Selina is obviously a highly skilled thief - saying that she was forced into her life of crime by social inequality is not particularly convincing. There's no indication that she was ever starving - and if she was, when did she have time to learn how to crack uncrackable safes and do jujitsu in 4 inch heels? As for the kid and his talk - I would have very much liked to have seen more of that storyline, as it was his vague mention of lack of work for his brother as well as his faith in the Batman as a savior figure - a person supposedly considered by the entire city to be a ruthless murderer - seemed very out of left field with no follow up.
Furthermore, if the power structures of Gotham were clearly corrupt and oppressive, who does it make Bruce Wayne for the story to begin with him hosting all of them at his home, apparently not for the first time. This is my very issue with the film - it's full of mixed messages.
Bane's "revolution" was clearly able to garner a significant amount of support, even if it didn't have the support of a majority of the people; the sheer numbers of people participating in the expulsion of the rich from their homes and taking over their dwellings demonstrates that. Even if a majority of Gothamites didn't support Bane's "revolution," it's clear that many had become desperate. And as the Joker put it in The Dark Knight, "Let's see how loyal a hungry dog really is."
It's not at all clear that many had become desperate. That's why the "revolution" feels so bizarre in the middle of the story. A single scene of an orphan who lives in a boy's home saying his brother is having trouble finding work really does not go nearly far enough. The scene in BBegins when Rachel takes Bruce down to Lower Wacker drive and shows him people living on the streets did a much better job of creating the sense that the city was rotting from underneath. You don't get anything like that in TDKR.