Bikes 🚲

ok, so i'm really trying to understand zone 2 training. hypothetical - this isn't how i train, not looking for training tips, just trying to understand the difference. 
let's say I ride religiously 1x week for 3 hours. in study 1, I ride fully in zone 2 in study 2, I ride in zone 3. both are on a trainer with the same settings. after 6 months of this - what's the difference between these two?
i feel like i have an intuitive understanding that does not align with what I believe I've heard/read.

It’s about long term adaptation of your baseline aerobic efficiency.  Baseline is key here. A key idea is that our bodies respond more to sustained, hard but manageable, repeated behavior than short efforts that lead to exhaustion. You are training your individual cells to be more efficient not only when you are full gas. 

Base building is only one part of a training plan. You aren’t going to get faster only riding zone 2. You need some faster than threshold time as well.