Well it’s being going on for 15 years or so at Chelsea not just the last few years, 5 or 6 years ago they were arguably even more dominant, others have learnt from them . You can’t really explain the difference between them and us in a few sentences, and my view will be different from others.
Try this as a comparison though. After Abramovich took over they restructured their club and along the way made a commitment to creating the best Academy in the world. This was supported by Abramovich and they ploughed money, resources like Cobham , new scouting and coaching systems etc into it. Everton also have a “ desire” to have the best Academy in the world, I know this because David Unsworth said it last year when he became the Director of Academy. Other than that statement I've seen no evidence since that we have any desire in our club to even develop our Academy let alone a desire to be the best in the world. I don’t blame Unsworth for this, except maybe for stating a laughable desire which we will never even get close to without a commitment throughout the club , starting from the owner down .