Ok, I see 3 issues with your post :
1. Incorrect or at least hugely unsubstantiated :
You're demanding a citation for my assertion that houses are burglarized and burn down more often than once a millennium
I live for 10 years in a city with population that has increased from 4.5 million 10 years ago to 6 million now. There have been precisely 4 big incidents of fire - one in a very low tech market, one in an office, 2 in residential houses. The office fire was all about smoke - building + furniture survived but basement fire released such smoke that some people were suffocated / jumped to death. Out of about million houses in 10 years. Expectation value of a particular house being destroyed in fire - less than once in a million years. NOT taking into account people burning their cake in an oven in an attempt to bake it - as I strongly recommend not keeping backup hard disks inside an oven in use.
Burglaries are more common, but complete burglaries are nearly unheard of. Burglars are scared - so they quickly grab cash, gold, and sometimes small electronics that they understand - like mobile phone. So yes, I am not sure data loss due to burglaries or fire are more than once a millenium events.
The post I was replying to already admitted those events happen once in 100 or 1000 years, so if you argue about whether it is 1000 or 100 years, it is pedantic in that regard. Without even the rigour of citation expected of a good pedant. My saying "once in a millenium events" was merely a way to refer to the events that parent post was referring to while admitting they happen in 100 to 1000 years.
2. Strawman, or at least misunderstanding the gist of my post :
I'll play the same card against you: Citation needed that local backups are more cost effective.
I was arguing that the policy of "safest backup first", to the extent of protecting against once a millenium events (admitted in the post I was replying to) results in no backup at all due to people postponing difficult activities. This is human nature, and your misunderstanding it will not make it better. You don't even assert that this is not how human nature works, so your argument is addressing the strawman in that regard.
3. While arguing about remote backup being "cost effective", you completely ignored cost? Short term memory loss? Calculate the cost of dropbox account as compared to a USB drive per year and get back to me. The cost comparison is so laughable that I guess I don't need to compare but just mention that you forgot to take the primary motivation into account. It is like going for shopping and forgetting to shop and coming back home, but maybe it happens to you due to a medical condition. Hope it doesn't happen too frequently.
You also didn't take into account the upload bandwidth that would be required for online backups that most people don't have. And I know multiple people who depended on MegaUpload for backup.
Again, I remind you of an aspect of human nature - the following don't happen together :
1. spending on cloud backup,
2. even after MegaUpload and Snowden
3. by a non-geek
4. before a data loss actually happens
5. In spite of internet bandwidth and data limits
Reduce the cost drastically by asking them to get a USB drive and backup manually/TimeMachine/windows backup, in a few months - can happen much more easily while saving from less damage vectors.