Are lay articles good enough to be the main source of information for PhD research?

I find the entire premise of the question quite odd. First of all, to answer your question: I’d say that in most cases I’ve encountered the answer would be no, you can’t use popular science articles as a primary source.

That said, I seriously doubt that they’re all that’s out there. Google works on this problem: they came up with it and no one else ever heard of it or studied it? How did the popular media hear about this amazing idea that has somehow eluded the entire AI research community except Google and your advisor? I feel like you’re either looking at the wrong sources, your advisor is not pointing you in the right direction, or something else is off.

From the way you describe, this sounds really strange especially since there is a lot of real research in AI. I cannot believe you could only use those articles. However, your supervisor is the right person to ask - most likely, they alone will decide whether or not your dissertation is enough.

Answering for anyone who comes across this question from social science etc. as it is a bit different. We can use popular media sources, but only for certain things.

As someone who uses popular press articles as a "source" for my research, and who advises students who do the same, there is an important distinction to be made and a significant amount of methodological explanation required before you can use much popular media.

The distinction: you can use popular media as a source of information: of facts, or, perhaps, as a source of contemporary public commentary around a subject. You cannot use popular media as a source of analysis. So, for example, you could use popular media articles from the time period, in conjunction with legislative records, to understand the details of and popular sentiment about a change in Australian tax law in 1980. You can't (only) use a post on medium as a sole source of analysis as to why that tax law change was academically significant.

The explanation: you have to indicate that you are fully aware of the drawbacks of using popular media as a source of information for analysis, that you have considered the issues with doing so. You then have to show why it is methodologically necessary to use the media source. I use a lot of local Latin American crime reporting in my research, which I cross reference with government records that I have access to. The local reporting adds context, flavour, and a bit more detail to the government records, sometimes revealing types of information that don't exist in official reports. Media sources also provide names of people that I can follow up with. I note this when I explain my research methods.