There are only two classes
Society is made up of many social groups based on different things like occupation, economic status, gender, cultural background etc. But to achieve a truly egalitarian society there are only two kinds that matter. Whether you are employed or own a business. Everybody is working, so the term working class is misleading. The point is do you have a boss or not?
The separation of academic and manual labour is dividing. All employees must unite to gain power against the owners of the means of production. It's in the interest of the middle class to act in solidarity with the poor. Their privileges are only temporary and conditioned by the capitalists - the owners. The true division of power is between who owns and who doesn't. The social liberal deal with capitalism is a Faustian deal. The social rights and economic security will never apply to all. There will always be a precarious class to keep prices of labour down. And the mechanism of capitalism will inevitability accumulate the resources at fewer and fewer hands. There is a basic lack of moral at the heart of capitalism. By accepting and supporting this, the employed middle class is corrupting itself, when it instead should realize its sameness with everyone else also depending on employment for a living.
We should stop talking about the lower, middle and upper class. Stop separating between working and academic classes. All employed people must unite. It would strip the owners from their powers, and create a real possibility to share the fruit of all work equally instead.