That maybe the case. But the one consistent is that battery's get larger because people want more range - as you say, motor's are not suddenly becoming more efficient or more powerful by any margin. This is the same with lightweights - (320wh > 360wh > 430wh).Perhaps we should get you journos to educate their readers that range is in reality one of the least desirable tests to base on the next time they get their wallets out to buy a new stead.
It might be undesirable as a test, but when people get their wallets out, they want to know the bike will give them the ride time/runs/distance they have in their mind as a requirement.
Yes, we can all select different modes and even change the power in those modes, but it's still nice to have some baseline minimum you could expect.
Someone might make a dreamy smooth, quiet, supportive motor which weighs 1kg, the bike might be the most incredible thing ever to ride. But if you find that the most you can get out of it with full assistance is 10km's and 500m's climbing because they screwed something up along the way in how the power is used/delivered, it's going to have a very niche market because you're close to the balance point where you have to turn the assistance down so much to get usable range that you might as well buy the version without a motor and have an even lighter, cheaper more reliable bike.