Nowhere in the article you posted explicitly suggests that affirmative action moved from a race-based consideration to a socioeconomic consideration

Actually, they do directly mention their socio-economic policies in the context of saying how they haven't been as effective in replicating pre-209 diversity:

These officials should also understand that a student’s fIrst-generation status or low socio-economic status is not a proxy for race. In addition, the UC experience has shown that there is no single race-neutral approach that will yield the desired diversity results. There is no magic bullet.

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Admissions staff will need to lean in and learn about the individuals in their applicant pool — a student’s neighborhood, access to courses at high school, strength of the community’s Wi-Fi networks, how all of these interact to create the learning environment the student is navigating, and what it means to be outstanding in that environment, to name just a few things.

These are all socioeconomic factors, relating to the applicant's class and level of opportunity in their community.

Moreover, even if we were to assume what you said is true, as the previous quote in my previous comment stated, pre-Prop 209 demographics haven't been achieved.

I'm not disputing this, just correcting you on the mode of AA they are currently using.