Not intending to offend, but for 90+% who have stored 2 years, they waste quite a bit of it. Yes, there are those who don't, but most do.....
Additionally, you have to survive 2 years in order to use it....
Lastly, 99% of all issues will be done in far less than 1 year.... though there are exceptions of course.
So having two years worth of food is silly because some of it might be "wasted" (not really sure what that means), so having only 3 months worth is a good idea? Not sure how that logic works. If I "waste" some of my 2 years worth, I still likely have 18 months worth, which is still much better than 3 months worth.
And where you getting that 90% number from? I've been prepping for 25 years, and most of the people I interact and associate with have been doing it a long time as well, and I don't know anyone whose "waste" is notable enough to make them change tactics. Was there a survey or study of some sort that I am missing? Same with the "99% of issues will be done in far less than a year" number. Statistics are not just numbers pulled out of the air....you need to explain how those numbers came to be.
Yes, there is waste to a degree. This past fall I did an inventory, and separated out about 200 cans of various sizes and content, which were over 15 years old, and whose can was iffy looking. Those cans went straight to the barn, and I open a few every week for the chickens to eat. Of the over 100 I have opened so far (mostly corn, beans, fruit cocktail, peaches, etc.) only 8 or so were actually bad, and most of those were carrots! (Canned carrots have a horrible shelf life, in my experience!) The rest I would have eaten, no problem. The chickens are an important part of our preps, so I don't consider rotating older stuff to feed them as "waste".
I also have stuff in the freezers that I know needs to go. Much of that will go to chickens as well.
I "lost" about 200 lbs. of "scotch broth" mix around 10 years ago. I had mixed it all up and stored it in 2 liter soda bottles. Something chewed up those bottles and it was contaminated enough that it too went to the chickens. That truly was a loss, because I worked hard to put that together, but it still isn't enough of a loss to stop me going forward.
Honestly, I have thrown away more "bad" food from my weekly grocery shopping trips than I have of my storage food over the years.
I guess prepping this way isn't for everyone, but please don't discourage others from doing it simply because you are not able to do it.