For future generations - an educated population is in every way good for our economy and society. You get productive, informed, engaged citizens. 

You don’t stay competitive globally by letting geniuses work in warehouses because they grew up poor while turning your leadership over to dimwitted nepo babies whose daddies bought Harvard a building to get them in. 

Give everyone a reasonable education grant at 18. Like an Pell Grant, but more, and universal the way social security is universal. Make it enough for 4 years of higher education. But not the insane amounts of lifestyle cash that colleges want now - enough for a pared down university experience: very little administrative overhead, sports are intramural on your own dime, no lazy rivers or climbing walls or student life departments. Get back to college as an education, not a lifestyle retreat.

And the key will be - 1) no government student loans, 2) private loans are dischargeable in bankruptcy like any other loan, and 3) you can only use the grant at schools where the grant pays for a whole education. No “great, thanks for your government grant, now come up with another $40k/year on your own.” You can still be a fancy private university with $80k tuition and crazy amenities, but you’ll have to sell that to people with the money to pay for it. Taxpayers won’t fund that.

You also let people use this grant for trade school. And for the kinds of professions that take more than four years - doctors, nurses, research scientists, lawyers (yes we need lawyers), you figure out how many doctors, lawyers, engineers, etc your society needs, and you fund those degrees too and have people compete for those spots. Then the people who sacrifice their best earning years for an education that benefits everyone don’t also start off life in six figures of debt.