Those particular random LEDs just happen to be that way. LED efficiencies vary easily by three order of magnitude. Best are around 50% of electrical energy converted into light; some are like 0.1%, a lot worse than incandescent bulb.
Comparing any random LEDs is like comparing a skateboard and a Formula 1 car because both have four wheels.
Human eye is most sensitive on yellow-green range, and less sensitive on blue, but the difference here is something like 2-3 times, much less than a possible 10x-100x difference between the efficiencies of randomly selected LEDs.
The differences are especially very large in green LEDs; very low-efficiency green emitters are still widely manufactured and sold, and easily found in your parts bin, whereas very inefficient blue leds existed only shortly, and are rare in people's part boxes.
But you can get a green LED which is as efficient as the most efficient blue LED (or at least close), in which case it looks brighter at the same power input. For such high-efficiency green LEDs, the Vf is also close to the Vf of the blue LEDs.