Washington state already has a very successful program called Running Start that is very similar to this proposal. Starting their junior year, high schoolers are allowed to attend a community college instead of (or in addition to) their local high school, all paid for by public school funding. I had the great opportunity to participate in a program at my local CC called Ocean Research College Academy. ORCA gave me the opportunity to earn my Associates Degree while I finished high school (with college courses standing in as equivalents for high school requirements), all while having actual scientific research experience. Heck, recently they started maintaining an underwater monitoring station for the State Department of Ecology.
(Commentor medeii gives a better explanation of Running Start above.)
Of course, there's the concern that students doing this may be brain-smart, but might lack the emotional and social skills gained in a high school environment. Some of my own family made that concern clear to me when I applied for this program. However, because of the nature of ORCA (where students have to make an effort to apply and be accepted), the students there were predominantly highly-motivated and socially capable.
Anyway, I got a terrific education, earned an AA degree while I was still in high school, and got 2 years of tuition paid for by the public school system. Also I made some awesome friends.