absolutely. you would just go to the browser cache folder and look for the file that was increasing in size as the seconds passed. This is why I disagree with the comment above that you can't defeat piracy through technology. I think there are plenty of people like me who routinely kept music/video through tricks like that who are now thwarted by whatever the heck html5 thing browsers started doing in the 2010s.
If you could find a file in the cache folder you are fully capable of typing `yt-dlp URLHERE` in a terminal. I taught my dad how to do that around 2010 or so so he could save his religious music to his computer.
well yt-dlp didnt exist in 2010, so no you didn't. At some point he had to move from youtube-dl or whatever it was called to get the new fork. and looking at yt-dlp's github I see how often its tricks get shut down by google, and old releases don't work. Every few months. That inconvenience alone will discourage many pirates and save a lot of money for content providers. Just as there are many users users will at the margin economically there are many at the margin of competence or drive.
I've been running a YT-DLP build for a year now, no issues. Even I am surprised.
People who use tricks like this will always be in the minority. This is harder than going to TPB.