Can't YouTube serve up the videos in formats that the original Chromecasts can consume? Surely either YouTube can know which Chromecast is making the request, and serve up an appropriate quality, or allow the Chromecast to request a lower quality version of the video. To be clear, I don't expect to be able to see videos in higher quality than was available at the time of purchase. I expect to be able to 'watch YouTube' as was advertised on the device's box.
This infuriates me. Google must know about this, and can surely lower the bitrate for these old Chromecasts, yet have chosen not to. Every time I encounter this on my old Chromecasts it reminds me of how they ruined the Nexus 7 with its final major os update. Blatantly trying to get people to buy new devices. Do no evil, my arse.