I've noticed, in my actual life, that there is a difference in attitude when you have more than just enough money. It is no longer money you have, but power.
I've been told -- I don't know this on my own -- that generosity is much more common among the poor than among the middle class or wealthy. It seems likely, and especially so if what you mean by generosity is sharing food or access to shelter or cash, when it is available. When you are poor enough, family and friendship may be more enduring and reliable than are food, transportation, clothes, or shelter. If that is so, then generosity will inevitably take the form of sharing whatever of these things are available.
This a a natural and basic form of sharing, and there are many attempts to induce the not-poor to share in similar ways. One example is collections for the food pantries, which are always promoted as opportunities to share actual physical boxes and cans of food. Whether the poor share more readily overall, or more broadly among strangers and people who are only slightly connected would be a question for someone with actual facts to write about.
Among somewhat wealthier people, money takes on a different role. People with reliable and adequate incomes tend not to think in terms of food and shelter, but in terms of having enough money to be sure of being able to obtain whatever food, clothes, cars, and houses they may need as the need arises. Many of these people are also generous, but their generosity is more likely to be carried out and, importantly, to be understood in terms of money. Most charitable organizations solicit donations from this group of people, and they ask for money: "Your gift of $25, $30, even $50," they write in their form letters, going on to explain what wonderful work can be accomplished with those gifts.
Money is what these people believe that they have, and it is money that they do or do not share with others. Seen another way, however, it is not money itself but a confidence in the future that they try to share. There is a reason for the popularity of phrases like "safety net" when talking about charity; it is that the intended result of charitable giving is to give confidence to people who are at risk or (in the more popular phrase) "living on the edge".
At some point it is no longer money that we have, but power. I can already see the change in my own life. When I had enough money to live on, I gave money to churches and charities. As I moved beyond having enough money to live on to having enough money for the rest of my life, I found that instead of sharing money I was sharing my power.
When poor young adult friends come to me wanting to continue their education, they ask for money. What I give, however, is a demand to the school that they provide services to my friend. I say, "Here: You have the resources you need, let my friend go to school." And I address the school in my actions, or at least in my intentions, because I am exercising my power on behalf of my friends.
This is still generosity, but it has a different character. The poor share as equals; no one has much, and the one who is lucky shares with the one who is not. In the middle, the people with economic confidence share money in the hope of providing similar confidence to others, who are less certain about their future. For the economically powerful, sharing takes on a character of exerting power on behalf of others; there is some hint of patronage or chivalrous nobility, but in the example of paying tuition the long-term goal is clearly to ensure that the recipients will gain at least the power to become independent.
In the extreme, among the very wealthy, giving money can become a caricature of true generosity. Thus you see the Resch Center, the Resch Auditorium, the Resch Aquatic Center, and the Resch Family Trail. Not to put down Resch's public spirit, but he made millions overcharging churches for folding chairs and probably owes us the money. He does give away a lot of money to many worthy projects. It is the power that he isn't giving away.
The differences I've pointed to arise from the relative differences in wealth when the currency of sharing is material wealth. When the currency is something else, technical knowledge for example, the tables may be turned. The person who is poor in money may also be poor in technical knowledge, but that is not always so. Rich and poor may be equals in some other realm, and in that realm might share as equals; this is not a certainty, but it is possible.