the point about moderation is key. To achieve success in this dunya, yes you have to work hard, attend school, struggle to get to the top of a fortune 500 company, struggle to grow your business etc..
but it can not be done by sacrificing the deen. If one can combine both aspects, then he/she is successful.
Not everyone in the world can become Sufi's and stay in constant Dhikr 24 hours, and not be involved in the Dunya. Everyone plays their key roles. We need Muslim Doctors, Lawyers, Engineers, Shopkeepers, Policeman, Army, etc.. but we need ALL of them to be Following the DEEN.