Google began by offering the best search engine. In its early days, it was clearly better than the competition and quickly garnered attention because it was both free and incredibly useful. The search results were solely to third party sites, rather that its own properties, and it even rad ad-free for the first 3 years. It's been 20 years since Google introduced ads, and the results are definitively more biased towards showing results that help Google.

Google's search results are now the standard for what's expected by consumers, and it's criteria have pushed developers and marketers to structure data in Google's preferred manner. It stopped being necessary to provide the best results many years ago. When nearly everyone defaults to Google, it's hard to be motivated to make the product better for consumers. Instead, it's much easier to look for how to expand in other areas.

For Google, that has meant changing results to include more Youtube videos, snippets of scraped content, and many more ads, often relatively indistinguishable from the "organic results". Often these results are either owned by Google or the data is taken from the third-party site in such a way to deter the user from ever leaving Google.

There are other options available for search, and it's hard to make a real argument against the quality of either Bing of DuckDuckGo. While neither generally benefits from the entire web development world adhering to their whims, both are extremely capable of crawling the web and delivering pertinent results. That's clearly not enough to win over most consumers who are not ensconced in the Google ecosystem.

At one point, there was a consensus view of Google as a non-biased search engine. That view is largely gone, and Google is well beyond it's days proclaiming "do no evil." There is a court battle looming and Google has lost some its key supporters:

Senator Mike Lee is the chair of the subcommittee and was also one of Google’s last remaining Senate defenders. But even he flipped, issuing a statement after the hearing basically accusing the corporation of being an illegal monopoly. Here’s what he said:

[Google] appears to be using its leading market positions in search and online video to engage in tying on the advertiser side of its business, essentially forcing the vast majority of demand onto its platform. In turn, publishers are also forced to use Google’s platform because there really isn’t any other option.

Google has prepared for years for such a battle, and it has seemingly put aside trying to serve the best search results. The focus has turned to growing it's own properties and protecting the company in the face of anti-monopolistic actions. While consumers once chose to search on Google, it's now the default engine, rather than the best and the results are increasingly biased towards serving Google first instead of uncovering the best results.