Because ultimately there is a conflict of interest between you as a search user, and google actual customers, advertisers who are often spammers themselves. Som

Because ultimately there is a conflict of interest between you as a search user, and google actual customers, advertisers who are often spammers themselves. Someone needs to pay for google search and since it isn't you... Google might have been better in the past, but since there is absolutely no serious competition whatsoever from a market perspective, Google technically doesn't really need to care about the quality of its search results anymore, only maximizing profits.