The key to great skating is still to have a very solid amount of explosive power in the legs. Any kind of figure skating training is next to useless unless you have trained your muscles to the condition where you have a great basis of getting quickly powerful acceleration to your skating. If you don’t have that kind of power in your legs compared to your body mass, you will never be a quick and great skater, no matter how much you do figure skating training.
Laine missed three years ago his whole off season because of his knee operation, and he was still recovering from that for about half a year, so his legs became seriously weaker than they were before that. He has had a lot to do to get even to the level that he was before his knee injury, and he is not even close to being where he will be at some point in the future with his explosive leg strength and stamina. This is what his trainer has said also clearly. He will not have the same kind situation physically, as Rantanen had after three years of training, because Rantanen never had to recover from such a nasty knee injury, that would have taken over half a year away from his physical training. Laine will be coming probably one off season behind Rantanen in his physical development, if he will even ever match that.
There is also a reason why Barkov and Granlund started their figure skating trainings only after 3 and 4 off seasons of hard for their leg muscles first. That was not just by accident, but there was the clear plan of getting their explosive leg muscles and stamina to the level that they needed to get them to have enough explosive power for very good skating. Only after that they started with the figure skating to help just polish a bit their skating. You really seem to seriously believe that the figure skating training made them so much better skaters. I can tell you that you are wrong with that, if you really believe that way. It only helped them polish their agility and make their skating a bit more economical. The years of hard work to get enough of raw explosive power and stamina to their legs was an absolute necessity to take well care of first.
Unfortunately Laine has had his clear setback three years ago, so I unfortunately see him being one efficient off season behind the peers of his age. But skillwise he is really second to none, and that is exactly why he has already accomplished 44 goals and 70 points in his 19 year old season, even when he has been physically way behind the other comparable young talents.