Most of the low-middle or lower class folk, once they paid for food, rent, isnurance, and gas, have next to nothing left. How do you propose they would buy share ? How do you propose they would buy enough that they would live on the dividend (which would be what , 3-5% in average ? Meaning they would have to invest upfront 20 time the amount they need to live per year) ? What do you propose they do if the company fold and their share are worthless ?
No what will happen is that the lower class will grow , until it reaches a spot where the lower class has nothing to lose in looting/rampaging a bloodshed, then at this point society correct itself by having more non automated duty, or economy crashes due to nobody having money to buy stuff, so company folds and robot investment get too expansive so only manual labor company get enough money, and that happen in a cycle until our life condition reach the same as developping country or a sweet spot is reached between manual labor/automated labor.
But knowing the greed of those of the upper class, I would bet bloodshed rather than sweet spot.