Overall funding has gone up - it was just focused on community colleges at the expense of UC, as it should be to avoid exacerbating economic inequality.
The community college system has been funded more generously, and not coincidentally, hasn't seen the same tuition hikes. You can still get an associate's degree that's almost 100% taxpayer-funded in CA, just no longer a bachelor's. (Cal State is kind of halfway in between, still much more state-funded than the UCs, but not anywhere near the per-student levels of 1990, which is why in-state tuition there is creeping towards $10k.)
This is an interesting observation, as the Cal States are more focused on instruction than UC, which I think helps justify their (and the CCs) better state funding. UC looks like its flush from all the federal research dollars it pulls in, and from running the hospitals, so the Assembly feels it's easier to cut there, than at CalState/CCs, where they don't have the research or hospital money.