| To be fair, I think Thatcher had a part in this too, not just Ronald Reagan.
The mid-80s was a time when they told us we were all doing fine but there still were problems like the Ethiopian famine, homelessness, hunger, drugs, AIDS, etc. The solution seemed to be charity concerts and songs, as well as public displays of charity. Somehow, the money raised would fix everything.
What made it different than previous charitable activity was the public nature of it. You see, the idea was to be all over the media showing everyone how charitable you were. Never mind that things like Live Aid cost millions to put on that could have just been spent actually helping the people the money was ostensibly being raised for.
I'm pretty sure this form of charity was directly a side effect of the attitude of Reagan and Thatcher as sort of clueless optimists, and the feeling in the mid-80s that greed is good and even charity had to be over the top and ostentatious.
An incomplete list of such events follows:
Others? node here. | 
