What's the point ot IT security

It occurred to me this morning that corporations spend hundreds of thousands of pounds on making their IT systems secure and introduce practices that constrain use of technology and slow progress all in the name of defending unauthorized access to their information.

(I acknowledge that another aspect of IT security, defence from malicious attack, is a different challenge)

Thing is - why bother. I struggle to find stuff on my own laptop when I wrote it, I labelled, I filed it and I know the context in which it was created. What chance is there of someone who picks up my laptop of finding anything usefull let alone someone gaining access to corporate systems with their laberynthine file systems, naming conventions, badly named documents and high percentatages of pointless worthless documents?