As others have said released yes but most a little illusive - I hope you manage to track down the ones you are looking for
It always happens at the end of a line - its why we have different generations
If G1 had sold to the same levels in years 8 and 9 and 10 as we saw in years 1 and 2 and 3 then the line would have kept on going for longer rather than being retired. But fashions and styles and trends change, so most lines have an expiration date which is easily shown in a final year or 2 of down trending sales as a company will need the sales fall in order to finish the line...and then start considering the new one.