There were other serious problems with the "2+2" community college model:
1. Sequencing due to prerequisites. If you have exactly 4 semesters, it makes scheduling prerequisite classes harder. One stumble in one semester with one class can completely derail the next semester. Spreading them out over 4 years reduces the impact of a single stumble early-on.
2. Difficulty of pacing yourself. With 4 years, you can pace yourself by spreading your hardest classes around 8 semesters, instead of packing 2, 3, or 4 into a single brutal semester.
3. Targeted core classes. Computer Science majors need advanced Calculus & Physics, but do a lot better in classes that teach it in ways that feel directly relevant to them. Say, by presenting everything as a game-programming problem. Throwing CompSci majors into a class with a curriculum designed for premed students is going to make them *hate* advanced math, even if they previously LIKED math. With 4-year schools, you can have multiple Calculus II & III classes that teach the same concepts, but present them in ways tailored to maximize the engagement of CompSci, Engineering, Science, Premed, and *literal* Math-majors by presenting it in ways that make it feel interesting & relevant.
This is also why, prior to making community colleges 4-year colleges, Florida started allowing/encouraging community-college students to take 100-level "majors" classes during the summer trimester at whatever state university was affiliated with their community college between years 1 & 2... kids who did it were less likely to end up in the "discovered in year 3 they don't actually like their major" group.
I'm not 100% sure, but I think most of the advanced classes taught at Florida's former community colleges are *technically* "dual-enrolled" -- at the campus of the former community college, but taught by professors of the affiliated university (e.g., Broward [Community] College, vs Florida Atlantic University) & open to students from both.
I do know, however, that in the early 1990s, Florida's community colleges were a hot mess, and most students ended up on "the 5 year plan" (and often, 6).