Why do people necrothread?

From my experience, they google a topic, find a thread, and then post on it without checking the date.

For example say I searched, "How to fix no audio from speakers". Then, I find a thread on a tech forum explaining how to fix. The thread is from like 4 years ago. I click on it, and the method provided doesn't work. I reply stating it doesn't work for me. I didn't bother checking the date.