The author's proposal, making Google's index publicly accessible, would leave Google search intact. Google's algorithm would presumably remain proprietary.
For people who like Google today, nothing would change. For people for whom Google falls short, there would be new options. Looks like a clear win-win for consumers.
This is not a good thing. Basic keyword searching on an index isn't viable to compete, then you go back to when keyword spammers were at the top. Google should be forced to distribute all their search technologies to the public with the threat of the Alphabet corporation being dissolved if they do not comply. That is the only way to get us out of this mess and break Google's stranglehold on the internet.
The limits of Bing, Qwant, DDG, etc. are not the number of the indexed pages.
It's that, give them the same pages, and the same search terms, and they don't return results as good.
But it's worth something. Giving DuckDuckGo direct access to Google's index, including the ability to train models on said index, would improve the competitive landscape.