It was always fitness, practice and speed, all linked.
Most of the stuff they do is wired and instinctive.
The gap has closed at the same time as they have improved.
The British game is boring & predictable with defences too organised & set.
Watch games from the first decade of Super League and you see multiple line breaks and exciting, fast play because the RFL cracked down on players being allowed to slow the play-the-ball. As a result, defences were frequently not set in a regimented line and players could exploit that (Cunningham and Roby at Saints were brilliant for spotting a disorganised defence, then scooting into that space from dummy half, creating more disorganisation, so on the next tackle Saints would very often break a ragged defensive line and frequently score)
In 2008/2009, the authorities declared that more latitude would be given to defenders to clear the tackle. Some coaches began to take this to the extremes - Brown at Huddersfield, then Maguire at Wigan who introduced 'the wrestle' to extend the time the tackle seemed to be in progress and get the tackled player on their back to slow them getting to their feet even more - 'turtling' - followed by defenders timing their 'flop' onto a player being tackled to be just before the ref says 'held' then the 3/4 tackling players peel off one at a time. As that proved successful, more coaches followed and developed further techniques. The result is that with almost every play the ball, the defence is set. Then you have defending teams rotating the duty of rushing at the first receiver as soon as the ball is played, so they have no time to do anything but accept the tackle.
Abolishing the scrums and bringing in the 6-again (both temporary measures due to Covid) have made it worse. Then you have Warrington who, whenever an opposition player does make a break and Warrington's defence near their own line is in disarray, one of their players - usually that whingeing lump Chris Hill - will lie on the floor holding their head so the ref stops the game whilst the physio/doc runs on. By the time play restarts, the Warrington defenders are recovered, got some air in their lungs, and fully organised. Threat averted... by cheating.
The British game is going backwards.
