Can't fault this logic.D3 seasons and rifts worked like the carrot on the string analogy. It had you keep coming back. The game is meant to be a grind but D3's reward loop was stimulating enough. D4 was a massive own goal. They nailed the story experience and the world is darker and more grim than 3, but the entire end game is just the grind part with very little reward.
I still have faith in the long term though. Blizzard don't stop supporting their main games and D3 was poo at launch too and it took until the Reaper of Souls expansion before it is what it is now.
And you know what, when the expansion rolls along, i'll gladly smash that out also. Fingers crossed - with that comes the similar dangled carrot of something similar to rifts/greater rifts/set items/...... Cow level?