Interesting point.
But the easiest thing for me to control is the output power of my PV. Sure, pressure, temp, etc. all affect my vape. Luckily, the vast majority of my vaping is done between 70-74 degrees F, at 500 feet above sea level, at 45-55% humidity. Even if I am vaping outside in different conditions, and I need to adjust my voltage output, I can do it once for the new environment and enjoy a consistent vape. Everyone not in a 100% controlled environment suffers these variations you list, to be sure.
I eliminate one variable that always changes for everyone not using a handful of PVs that actually put the same voltage every time. I despise the output voltage drop losses in vape production, especially after having a really nice vape with the fresh battery.
If it doesn't bother you, good for you. I wish it didn't bother me so badly, because I think my Caravella is one great looking mechanical mod! I just only want to vape it for about 15 or so puffs before I feel like I need a new battery...and I don't want to go about with six batteries when I leave my house for a few hours. I can take one 18650 in my ProVari, and it will put out 4.2 volts for eight hours of heavy vaping. I am not saying its better than your mechanical, I am saying it suits me better.
Part of the beauty of vaping today is the wide diversity of devices available. Everyone who feels the urge should try them all and pick what suits their vaping profile best.