You can't really just say this, because it's like comparing apples and oranges. You may be confusing voltage drop with sag. 18650s drop the voltage more over the life of the charge, but the LiFePo4 actually sag more. Cells no matter the configuration, pouches, or 18650 come in different chemistry's, and discharge rates. The stock battery that came in my red bike was a high discharge LiFePo4 chemistry made with pouches. My new battery pack is made with high discharge 18650 30Q Samsung cells rated for 15 amps. It out performs the stock battery by a small margin. My limiter is set for 65 amp, but usually recorded 67 amp with the LiFe pack. The 30Qs see 69 amp before the limiter can hit, and I see a couple hundred more watts.The problem with 18650s is they sag hard when you try to pull their rated amps. Or even a fraction of their rated amps, as compared to pouch cells. You do not see 18650s rated for 10c continuous.
Imagine this with your Juice ebike of course in frame as a production version...Well I sold my electric bicycle, I'll miss it. 50 mile range is not enough for me I need 100 to be happy using throttle only w/some pedal assist. To be where I needed to be another $1300 battery was needed to accomplish the task. Too much money just can't do it. Some day maybe but not today. I do like electrics though, so quiet and torquey if you have a 750 watt motor. Just wanted more range, the co I bought from stated 100mi range. It's doable with an athletic person w/lots of assist. Well that's just not me. Back to gas motors and I'm excited w/the 53cc's available and that new GX 50cc coming out. Gonna try a GEBE kit out this time.