I haven't used the Llama 4 10 million context window so I don't know how it performs in practice compared to the major non-open-source offerings that have smaller context windows.
But there is an induced demand effect where as the context window increases it opens up more possibilities, and those possibilities can get bottlenecked on requiring an even bigger context window size.
For example, consider the idea of storing all Hollywood films on your computer. In the 1980s this was impossible. If you store them in DVD or Bluray quality you could probably do it in a few terabytes. If you store them in full quality you may be talking about petabytes.
We recently struggled to get a full file into a context window. Now a lot of people feel a bit like "just take the whole repo, it's only a few MB".