As I mentioned here (https://news.ycombinator.com/item?id=31305712), because it’s targeted at a different audience and because it being separate allows it to be iterated and experimented with more quickly. When you have an install-base as large as Windows, you have to be careful with what you include as a built-in feature versus what is an add-on or option (even first party), because a change made for one class of users could be confusing or detrimental to another. This is particularly true when it comes to utilities and features that are iterated on in public and with great frequency. PowerToys occasionally ships with bugs or crashes that are completely acceptable and manageable to the audience of power users (and are usually fixed very quickly), but that could be much more of a problem if shipped to 1 billion users (and the steps you’d need to take to test against edge cases would slow down development, and the development speed is one of the best parts of PowerToys).

You can install it through the Microsoft Store, WinGet, Choclatey, Scoop or directly from GitHub. It would be nice if there was maybe a pointer to it inside the OS to alert some users of its existence, but the premise was similar to the OG PowerToys, which were downloadable off of the Microsoft website.

As I said in the linked comment, stuff from PowerToys does get upstreamed into the Windows shell, sometimes with modifications or refinements, but some of the utilities are things that wouldn’t necessarily make sense to be included by default.