Yes, we can avoid to buy those products, but the issue is, like the article says, the monopoly. If all the products are made by the same company/ies, only with different sub-brands, then the politics and magistrates should take a look into it.
I have been consciously trying to cut down on the expenditure on snacks, food (like eggs) and other items like laundry detergent that obviously have gone up significantly in price (more so than inflation rate) and/or have been shrinkflating noticeably. It is not easy, but that's the best I can do to send a message (I know, me doing alone is inconsequential) to some of these producers that they have a limit on how much they can raise. I am also 100% aware that a lot of people (esp. the ones with families) don't have the luxury to reduce consumption like myself though.