I guess it depends on what you mean by "difficult".
Chrome is unfortunately limited here by the security of the OS. No popular desktop OSes have application isolation: all apps have the same permissions. Any app can write to any other apps' storage.
This means that if Chrome makes sideloading too difficult, developers will just tell users to run their native code which will hack into Chrome, making even understanding what extensions users have or uninstalling them impossible. Sideloading on desktop OSes has to be hard enough to discourage most users but easy enough that developers like adblock don't start looking for an even bigger hammer.
This is what I meant by delicate balance of incentives.
I absolutely understand and I agree with you. I suppose you have much more data and probably research. But on the other hand I believe Google also has literally infinite amount of developers.
Thus, it should be easy to classify and make that specific dialog more visible - especially when side-loading.
I think it definitely is hard job to reach consensus on all the fronts.
For some programs sandboxing can work perfectly fine, but for others it can result in anything between noticable UX degradation and a major PITA, because there are enough workflows out there that can't really be sensibly made to work with an "every file access must go through an official 'File open'/'File save' dialogue (or something comparable, like drag-and-drop, or launching a certain program with a certain file)" model.
Chrome is unfortunately limited here by the security of the OS. No popular desktop OSes have application isolation: all apps have the same permissions. Any app can write to any other apps' storage.
This means that if Chrome makes sideloading too difficult, developers will just tell users to run their native code which will hack into Chrome, making even understanding what extensions users have or uninstalling them impossible. Sideloading on desktop OSes has to be hard enough to discourage most users but easy enough that developers like adblock don't start looking for an even bigger hammer.
This is what I meant by delicate balance of incentives.
More info here: https://news.ycombinator.com/item?id=4954915