Yes, that point is pretty low for JRA. It's higher if you're doing real base at a good endurance pace. The point is to be doing AS MUCH WORK AS POSSIBLE given the AMOUNT OF TIME AVAILABLE TO YOU. High volume necessitates low intensity. Low volume necessitates high intensity. I argue that the first scenario is preferable to the second. It's as simple as that.

The Pez article is dumb in that it does a poor job defining "LSD" miles. Yes, I agree if you just go out and spin along at 130w for 4 hrs, you're not doing a whole lot of good. "Getting the most out of every second on the bike," while riding 20 hrs/week, necessitates a slower pace. Hence lots of time in zones 1 and 2.

Z2 is higher than you think. It's not spinning along with grandma. For me, it's 200-220w, just hard enough that I have to sort of pay attention to what I'm doing. Cruising, "junk miles" pace (or, recovery pace) is about 30w lower.