This may be a blasphemous question: Is there a contribution of Marx that actually makes logical sense and can be deduced praxeologically? I doubt it.
There's no such thing as a proletariat.
"Does Marxism account for the unemployment levels we are facing today? How is sitting at home unemployed and getting paid a form of slavery? Wouldn't the bourgeois want us to work even more for them at lower and lower wages? We're not seeing that separation of bourgeois and proletariat intensifying."
You fail to use the Marxist logic
The Bourgeoisie is in it for itself, it works in its self interest. With this being said it will always try to preserve itself. In the past what you said above is exactly what happened, but when the proletariat showed signs of revolting the bourgeoisie made concessions to ensure that it would not be overthrown by the proletariat, this included things such as unemployment and so this continues in order to ensure the proletariat does not organize and revolt against the bourgeoisie