You could. But youtube's website itself would fail this "only 10% at once" test.

Why? IIRC you can flush the SourceBuffer in Media Source Extention and only keep a small part of the video in the browser's RAM at all time.

(It won't work for Youtube shorts though, because 10% of a 30s video just isn't enough for reliable smooth playback)

	▲	superkuh 5 days ago \| parent [-]
		I understand now that I was talking about how youtube currently works and you two were talking about how youtube could be contrived to work. Yes, it could. It'd only just waste more bandwidth having to redownload and cause more pauses. But people who buy things (the important ones to advertise to) have fast connections and everyone's locked in so google can focus more on advertiser issues over the lower end network user experience.