Not in benefit terms, in buying habit terms. CPI tries to be calculated on a regular basis, and thus is only useful if it looks at things people are actually buying. If people used to regularly buy steak, but due to production issues there isn't much to go around, where customers have largely shifted to buying ground beef instead, then steak is no longer a useful item in the basket. It will get phased out in favour of ground beef.

Steak is objectively more valuable in the traditional sense, as evidenced by the price, and also quite arguably more valuable than ground beef in the "benefit" sense, but that doesn't matter. Ground beef is just as good in the basket as CPI only needs to see relative change in price. It is not measuring benefit.