And then there's roommates... I used to pay $600 a month for an SF house, and did this by having 2 roommates and a live-in girlfriend. Saved enough for a house. Much comes down to delayed gratification.
And then there's the ability to sleep at night without your roommate having a conversation next your door at 2 AM, a different set of roommates that expected only you to take out the trash, another roommate that blasted tv next to your door at 2 AM, having to switch out a good roommate with someone who might also be terrible when they leave, not having your own space to work and focus on the job and hobbies, etc. etc. There is no delayed gratification when there is nothing to work towards to as you slowly go insane living with people who have no idea what it means to be "quiet" at night nor have a basic level of accountability/self-awareness, even if they say they do.