In DOS era, in Windows 3.x era, why people trust their usage on PC at that time?

In DOS era, and Windows 3.x era, applications were produced in every seconds. People started to focus and explorer what PC could do for them and generate any values on their life or business. In this moment, I want to think more about on that magic period. Why people trust all the things that happens on PC?

Two major questions:

1. DOS and Windows 3.x(An complex application on DOS also) could not secure all of the important files produced by or collected by user. Simple commands like “Deltree”, “format” could destroy the universe that belong to the users’ PC, right?

2. Users may applied several backup/recovery utilities on the DOS to made it possible to perform recovery operation. But, …, the important files were still insecure. Copying, viewing the files are extremely easy.

Those issues were lasted to Windows ME, until Windows 2000, Windows XP that make it make sense.