Surveys don't tell the whole history but for sure social engineering makes people the weakest ring in the chain.

If scams/spams and phishing are not profitable they cannot be increasing day-by-day.

Anyway the hardest part to do a "public" system it to do it both secure and user friendly.

Example: People hates captchas and confirmation emails.

And social engineering can do amazing things.

Do you know how to by pass turing tests and captchas?

Just create a "free xxx site" and redirect to it the captchas images from the site you are hacking.

In not time you ill got thousands of tennagers helping you to broke inside that site. 😛