There are three incarnations of the average myth: deprecating reverence; deviance proclamations; and guru fairy tales.
Deprecating reverence - "That's so amazing. I could never do anything like that." - You recognize it's a great accomplishment; but you fail to realize that it was done by an imperfect, flawed, foolish, bumbling, stumbling human being not too unlike yourself. Yeah, be realistic. With zero background, it's unlikely that you will at 70 years old begin your first ever exercise regimen and win the very next Olympic Gymnastics competition. However, fear and pre-visualized failure are self-fulfilling prophecies. If another human has done it, you can do it. It's just a matter of will multiplied by time.
Deviance Proclamations - "Well, that prodigy couldn't have had a normal childhood; that athlete's diet is just too weird; that successful person just has such an odd schedule." - Duh. You recognize that they're doing something different; but you have to vilify it so as to protect your own complacency and laziness. Again, deviance from the commonplace is what makes exceptionalism.
When you say, "it's normal for people to eat like this, act like this, think like this, etc.," what you really mean is that it's common. Yes, it is common. Common isn't good, healthy or worthy of esteem. It is common to eat like crap. It is common to abuse your body. It is common to balk at hard work. Vilify the hard workers, the dedicated, the dutiful all you want; that vilified deviance you lament is the very grit which creates a bell curve. Feel free to sit in the fat bubble in the middle. But some elbow grease will have you soaring elsewhere in another quadrant.
Guru Fairy Tales - "You can do anything you want. Just look at me, and here's how I did it with less than one hour per week, a two dollar budget and walking uphill in the snow both ways." - The premise is largely true, but the method is bull. I like to pick on Tim Ferriss for this example because, well, it's easy. I'll leave aside "The 4 Hour Work Week" nonsense, as plenty of others have picked it to pieces. And I'll stay just within my immediate domain of expertise: fitness. Tim Ferriss is this guru who has sold a brand whose message is basically "all the results without any of the work." The titles of his books say all. But the funniest thing about his 2010 "The 4 Hour Body" is that, although it contains a great number of good factoids on intense exercise, ultimately it's a sham. The overt claim is that about four hours of "smart" work is all that's needed for exceptional physical wellness. Now, keep in mind, Tim Ferriss has never GOTTEN INTO shape. He's a lifelong athlete, holds some world record for ballroom dance, is into mixed martial arts training, and, as of late, got into rock climbing. So when, pray tell, did he ever experiment with only four hours of activity getting him into superhuman conditioning? The obvious answer is never.
Anyhow, the point is clear. Yes, you can do a lot more than you think. And yes, there is value in working smarter not just harder. But careful on your sources. Gurus are out there to sell a lie that is loosely based on some actual facts. You won't get where they are by doing what they claim. You will get to where they are by doing what they do. Unfortunately, in most cases, this means becoming a lying cheat. So, if you want to accomplish something big AND maintain some modicum of ethics, morality and humanity... you won't do it in less than an hour a week OR on a two dollar budget.
You may have to walk uphill in the snow both ways, because, after all, that would be weird, abnormal, and uncommon. But you can do it, even if you thought it was too late in life to get started. Don't worry. That's normal.