Yes, worsening conditions mean people need scapegoats. The people in charge of the political machine may not even necessarily be scapegoating (though they often are). Sometimes there’s just a cultural search for explanations and the reactionary reasons happen to win out by the time they reach the ears of someone who can do something about it. Also, improving conditions make it easier for activists to operate. More resources, more hope, more free time, less death. It’s not a 1-to-1 link and there are other factors, but there’s a connection. You can also look at things like unequal distribution of prosperity. The success of the black suffrage movement in the US followed a boom where white Americans came into tremendous wealth which wasn’t shared among the black population. And where black communities were able to get some for themselves and develop their own prosperity, towns were bulldozed, flooded, or otherwise destroyed. And of course we already know about things like red lining. Prosperity plays a major part in that story.