There are 24 hours in a day. There is always enough time to sleep, train, and get what you need to done for the day. I know of guys who get up at 4 am to get 10-12 miles in in the morning before going to work, med school and whatnot. Roger Bannister would train at his lunch hour and I can't remember the other guy's name but he would train at night after working all day (if someone remembers his name please post it).
I find sleep to be very important but still it is not enough to recover fully. When I am in hard training, I aim for 9-10 hours a night, but even then I am still quite fatigued but that is where the athlete mindset comes into play: even when you are tired, you need to fight that fatigue and still get your workouts in for the day. It is just that more sleep helps you recover better and energize you more.
Right on. It is about being disciplined. I find it interesting how some people make time to go on their phones during the day, watch an hour or two of TV at night, yet complain about not having enough time for studying, or running. When you are training, you need to put other things aside and make running your primary focus if you want your best results.
It is like anything else in life. How bad do you want it? If you want to be the best, you need to make sacrifices, whether you want to be the best doctor out there or be the best runner. I don't have a social life really and I am happy to say that because this life is not about self-pleasing activities or hedonism but rather it is about working hard and working for the Lord (you may disagree with me and that is ok). I am fine with not having a social life because I am running fast times and working towards running in the Olympics one day. It is a slippery slope. When you start to dedicate your life to running, you begin running times that you never would have dreamed about. And that fuels you to train even harder. When you see all those doubles starting to pay off, you understand why you made those sacrifices that the world calls crazy. And then you push even harder and run even faster.
When you start running 4:0x miles, 14:3x 5k, 30:xx 10k, sub 70 half marathons, sub 2:30 marathons, you understand where all your free time went: into training and achieving times 99% of the population will never run because, not that they have no "talent" or fitness, but because they are unwilling to put in the work. There is no "talent". There is just hard work.