Of course, Google cannot be expected to support old equipment forever. It is also the case that Sony and Panasonic could have elected to rewrite their YouTube apps to work with the new standard but have chosen not to do so. But it does raise serious questions for anyone buying, say, a Smart TV. Three years is not a long time for a television set or Blu-ray player (although arguably it is for a mobile phone) and, given that YouTube is such an important feature then the value and functionality is greatly reduced if this happens. How many people would wish to buy an expensive Smart TV today if they knew this could happen?
One answer is to use a separate TV streaming device to supply the "smarts". These are relatively cheap and it is more palatable to replace something like a Roku or Amazon Fire stick costing £35 every few years, rather than a complete TV that may have cost £1000. Even if the TV is smart to begin with - and it will shortly be impossible to buy one that is not - using a separate box makes a lot of sense.