1. Before the post-WWII GI bill, which sent an enormous surge of young men to college in the 1950's, the percentage of Americans with a college degree was measured in single digits (Bachelor degrees then were as common as Ph.D.s today). And, yet, we still somehow managed to have a functioning democracy[1].
2. People evaluate degrees based on financial outcome simply because there is no other way to justify spending a quarter million dollars on a degree. That is an order of magnitude more than it costs to deliver a high quality education[2].
If college were truly just about learning, you could start cranking out college-educated citizens for $20k a pop. At price it's an easy decision to make. Instead, colleges have become luxury resorts with a classroom as one of the amenities. They compete on things like best food, recreation and nightlife. It's not (necessarily) a problem to bundle education with fun, but you have to justify the expense to your customers. Colleges have chosen to highlight the differences in earnings between those with degrees and those without.
[1] Even worse: While I agree with premise that we should strive for a better educated electorate, someone arguing the opposite could easily point out that the increasing political discord is correlated with the increasing fraction of degree holders.
[2] The cost of the primary input has decreased: Faculty salaries have been stagnant for 40 years--for a given "level". But faculty salaries have actually decreased when you account for "title deflation". Colleges increasingly rely on "adjunct" faculty and delay the promotion from assistant to full professor. It is now common for PhDs to do two or even three post-docs (which can include teaching duties) before getting a first appointment. Thus, a 40 year-old academic today has a lower title and costs less to employ than a 30 year-old academic from the middle of the 20th century.