Maybe it's just me seeing the past through rose-colored glasses, but it seems that the "Work hard and know technology" founders were more common in the 70s, 80s, and 90s, in contrast to today's "Party hard and know rich people" founders.
I think the "work hard and know technology founders" have always been around. But honestly, isn't this somewhat of a self-selection bias and something that remarks on the monotony of modern university?
If you're a highly driven and entrepreneurial individual, are you going to stick around for 4+ years of enforced pace higher education?
You might be more inclined to stick around and finish if you didn't have familial support to fall back on if your entrepreneurial plans failed and you didn't have the credentials to secure traditional employment. Dropping out lets you get started on entrepreneurial plans sooner, but could leave you in a risky spot later if they aren't a success.
There are some exceptions to this pattern though, like Jan Koum and Andy Grove. We desperately need more of them in today's tech environment.