how much difference really would various fridge temp affect the food life stored within? [closed]

this question outdated by ~7 years -- What temperatures should I keep my refrigerator and freezer set at? --

ask how much temp a fridge or freezer should be at

but im very confused about how much difference is a degree or 10?

like if i leave it at 45 or 55, is it not ok?

on http://www.explainthatstuff.com/refrigerator.html

it says if you leave it cooler, the food would last longer

but how much longer?

i've kept vegs and other food for way longer than than what is 'advised' and they were completely fine

like the two popular 'when does X expire' -- stilltasty & eatbydate

these sites and likely other advise a 'super safe' date of when you throw out perfectly good stuff/food

brown rice is completely find way past the days claimed on https://www.quora.com/Can-I-keep-brown-rice-in-the-fridge-for-a-week-in-a-ziplock-without-it-going-bad

and some ppl say it's perfectly safe

on http://www.stilltasty.com/questions/index/90/

it claims that 'important to keep the temperature of your refrigerator at or below 40° F.'

if it's warmer than that, it claims that the 'types of bacteria that can cause both food spoilage and foodborne illness will multiply too quickly'

so are we saying before that temp, food would multiply at a 2x rate?

but then if you go above that temp, then food would multiply at a 100x rate? not sure what 'too quickly' means. is it really 'too quickly' or is it just fine?

it also says 'can cause' -- so like a 1% chance or a 99% chance

this info matters a lot to make good decision

you 'can' die every time you drive or fly a plane, does that mean you never drive or fly or go anywhere?

if fridge temp mattered so much -- life or death importance

then why don't fridge actually show temp? or show the temp on the temp control? as also seen on http://www.consumerreports.org/refrigerators/best-refrigerator-temperature-to-keep-food-fresh/

if it was actually important? im sure one day the leading edge fridge would make this 'innovation', this basic innovation happen.

please help as best you can as the previous question was helped

really appreciate a helpful answer among all this info everywhere