To understand the culture we need to understand the word to hustle. It is of Germanic origin and was borrowed into English from Dutch where it meant ‘to shake or toss something around’. Indeed this was its first meaning in English, a meaning which is now obsolete. In English it developed the meaning ‘to jostle someone’, usually as a preliminary to robbing them. And from there it generalised to any pushing or shoving designed to hurry something along.
In American English it had the meaning ‘to obtain by some energetic and possibly illegal activity’, and then moved to the world of commerce where some amount of fiercely competitive jostling was needed to get anywhere. The hustle culture of today is characterised by the attitude that you must really push yourself to get anywhere. Long hours, obsessive focus, nervous strain is required if you are to reap the rewards of success.
And while we are into hustling, let us not forget the side hustle. This is the money-making project you have on the side, the start-up, the invention, the small business, that is the real concern of your waking hours. Unfortunately for some part of the day you have to hold down a job which you find boring and badly paid, but there is always the hope that one day the side hustle will pay off.