Secessio plebis could be compared to XVIII century emancipation of middle class. It was a struggle between hereditary wealthy (aristocracy) vs acquired wealth of middle classses. Like American revolution and similiar emancipation in England and Europe.
Both sides were relativly wealthy people but birth rights were giving them unequal status.
So not really a conflict between rich and poor. But of course populist side claimed tactical class solidarity with city's poor people. Later on bipartisan system of optimates and populari stayed for years but the division lost its practical meaning.
I am not sure if you added any more information then in the article, nothing that would help me believe that slavery is the thing that ended secessio plebis.
> nothing that would help me believe that slavery is the thing that ended secessio plebis.
It's like saying that steam machine and industrial revolution bancrupted landowning class and abolished serfdom in Eastern Europe in XIX century.. It is perhaps true but it is also complex, multidimensional dynamics.
The wikipedia article concludes that the final law "eliminated the political disparity between the two classes" so I am asking(not contradicting you because I don't have the knowledge) if your conclusion is based on something solid or just your own guess? I am not convinced about your agument.