Big congrats to OP for steady progression and improvement this year!
I do think though that the notion of “significantly easier” or that anyone could do it is kinda naive/inconsiderate of other runners’ backgrounds. In terms of hours in a day, I agree that kind of mileage is doable because you will be able to make time for anything as long as you care enough about it. But what about older runners or runners with very complex injury histories? Many people can’t get much past 40 mpw because of chronic issues or surgeries that leave them very vulnerable.
Again, I’m glad that high mileage eventually worked out for you but I think the convention that everyone can and should progress to take that much impact is wrong. I’m a lot stockier than the guys I compete against and running is a lot of pounding for me. But this year, I ran ~25 miles/week and only 4 days a week but improved in every distance 400m-mile and didn’t lose a mile race.
Some people need volume and some need intensity. Tripping over myself at 7:30 pace certainly would not have done me any good. And I reckon elites like Donavan Brazier are the same way- he has tapped into some amazing 1500m potential but still stays at low volume because he had Achilles surgery less than two years ago.