If the only way to get trackers on the average person is to serve it from the same first-party domain, or to bundle it in with the giant 'app.js', you better believe they'll do that.

Right now, the fact that only a small fraction of people run adblockers, and an even smaller fraction block javascript, is what allows it to work.

In my case when every attempt fails I know it could be the side effect of some other privacy add on. If it's a random blog/news, that's the end of it. If I really have to use that site I open Chrome, do what I have to do, close it. Of course given a choice I pick sites that work well with only JS from a few inevitable sources.