I'm seeing now how difficult it is.
Ran from '98 to '02 in HS, XC and track all 4 years.
Quit for 15 years (although I did a 5k in 2008 off 2 mos. of training and somehow ran 18:33 at 24 despite running 2 miles in 20 minutes when I started).
Started running on a consistent basis in late May 2017. So it's been 4 years of consistent training and I'm still a ways away. But I ran my 3:24 on 37 mpw with no structure, no smart watch and no coaching.
Am at a consistent 50 mpw the last 2 mos. and seeing where it will take me. I could go up to 80 if I had to but I have a lot of other things going on too.