How a bout 4/4: I run, should say jog, 30-60 miles/week. I used to think I was running "easy", but now realize that approaching 60, my "easy" 7:30-8:00 miles were probably at least marathon pace. I might start runs at 8:30, but stupid pride would have me pushing slightly harder all the time and finishing 7:00 or even faster. In other words, accumulating lactate, however marginally, all the time. Always over AeT. I wondered, like most others here, why I was fighting niggles, injuries and illness all the time.
Finally got a HR monitor, tried Maffetone's 180-age, swallowed my pride, and slowed down to 11:00+ miles (initially). This was a shuffling jog compared to my previous running, but reflected how poorly developed I was aerobically, despite running up to 70 miles/week. I had to walk up hills I used to charge up.
Now, a few months into the program I jog 10:00 miles 40-50 miles/week almost effortlessly, and very happily, as all my joints are now loose and healthy for the first extended time in 45 years in the sport. I stopped beating the crap out of my body. Maybe I will get back to sub-9:00 or even 8:00 for daily runs as my AeT changes, maybe not. A long as I feel healthy and energized, I don't care.
I still do strides a few times/week, plus 10x100 in spikes every 7-10 days, and do resistance training every other day. My body fat is around 5-6%, but a lot of that is genetic.
So yes I agree on the aerobic running. But running 8:00 miles is not purely aerobic for a 19:00 5K guy. It is training the "Black Hole" of chronic (push-push) cardio. And that is a big reason why our bodies are wearing down.