It might be useful to remember context.
Atlas Shrugged was a novel and things that are said in there, while certainly reducible to her philosophy, reside in the context of the characters and the story. It is also a dramatization. Rand herself always said that in real life ordinary things are marginal while in a story they are to omitted if they do not support plot, them, characterization, etc. Her books were not about generosity, which is good as generosity as a theme sounds more like an after school special to be truthful.
Modern talking heads simply confuse the point by package dealing Altruism (as sacrificing yourself to society i.e. Comte) with goodwill/generosity (traditional). Altruism, which she reiterated in her speech quote you highlighted, is a core philosophic point that is the backbone of many other ethical and political justifications and she hammered the point to keep it unpackaged. Atlas Shrugged dramatizes that point. For general generosity, she didn’t spell it out since it was not a theme of the book but if you really want to understand it you can look at how she dramatized people’s actions. Notice that the heroes of the book consider how the government’s policies will affect others while the looters who preach altruism claim to want to help the poor while ignoring how their actions do the opposite (because they really want power). Dagny is desperate to get farm loads shipped so people so they will not starve. It is not a sacrifice, society collapsing and others dying is certainly not in her interests either, but yet the fact is true goodwill does not conflict with rational self-interest. The looters sabotage this, even redirecting trains to crony projects, while wringing their hands about sacrifice, unconcerned of the real harm they are doing. They know it conflicts with rational self-interests but expect others to compromise towards the sacrifice. Generosity and goodwill is not compatible with altruism and it’s all over the book.
There are many more examples of goodwill. Reardon gives his brother a charity check to make him happy and gets slammed for it. Reardon sees it as being generous and nice to his brother while his brother criticizes Reardon for being personally motivated and doesn’t want his name tied to the money. James Taggart expects Cheryl to love him for nothing selfish and treats her badly while Dagny actually tries to give her moral support. Stadlar thinks people are animals and not to be trusted while Dagny gives the tramp a warm meal.
You might not have noticed them since Rand was pounding the big picture while these flowed naturally from the characters, but they also happened for a reason. It’s just not the point of the story.