Mostly, it's weird to be in the position to tell young people that university is an enormous scam meant to sucker people who don't know any better into a gigantic mountain of debt that can never get discharged so you can learn a hell of a lot less than you would in the real world. Not only that, this debt is incurred to pay for football coaches, dorms fancier than any apartment you'll ever have, and administrators whose purpose seems to be introducing systems that necessitate more administrators. Exception for medical school, I suppose, since you can't really learn on your own when it comes to surgery.
* You could change to a non-impacted major - one with more spots open than students. If memory serves, this was none of them.
CCs tend to have much better faculty:student ratios and a much stronger teaching focus than many four year schools (including UCs) will, especially for lower-division courses. As a result, you can, with the right program, get a better lower-division education at a CC, than at a UC, even one that is strong in your course of study.
First of all, community college is a depressing place to be. It's like a cross between high school, juvenile hall, and the DMV.
For example, a lot of the students at community colleges are stoners who are only there because their parents have conditioned their financial support on college attendance, and those are the people who you will have to compete with for enrollment in impacted classes, and who will drag down your grade on group projects. The labs, libraries, and other facilities are pretty much a joke compared to what you get to use at a good UC or CSU, or even a good public high school. You are unlikely to develop personal connections that will help you build your career.
On top of all of that, transferring is not as easy at it might seem. You have to watch the transfer office like a hawk to make sure they don't screw up your paperwork. I had a guaranteed admission agreement, and even so, I caught multiple mistakes and miscommunications between the community college and the UC which would have voided my agreement, or delayed my transfer for a year. De Anza has one of the highest transfer rates in the country, so I can only assume things are even worse at other schools.
While you are trying to push your way through two years (at least) in this depressing and dysfunctional environment, your friends at CSUs and UCs will be enjoying higher quality classmates, instructors, and facilities, living the real college life, getting cool internships and other career opportunities, and making personal connections with people who will be successful in their fields.
In the end, the amount of money I saved by going to community college and transferring to a UC, compared to going to a UC for four years, adds up to the cost of a new Toyota Camry. That's a trivial amount of money, now that I look back on it years later -- a couple hundred dollars a month in student loans over a standard repayment term. Even people who are repaying their student loans don't bat an eye at spending that kind of money on a car, but for some reason people are apprehensive about spending it on two years of quality education and life experiences.
This may seem excessively negative, but I think it is a necessary counterbalance to a lot of the advice I see when this kind of issue comes up.