You're right. They're too fit now so there's no space. Reduce the number of players is the only way
Fitness is key, but so is the mental attitude that accompanies less time, smaller spaces, smarter coaching. If anything, the game is becoming a bit of a play school version of American Football...particularly with the sometimes ridiculous TMO touch judge, referee interactions. (Which, in principle, I agree with - thank you, Rugby League)
Yesterday's match, where seasoned Lions - the likes of Roberts, Davis, North, Wyn-Jones etc were outwitted and relentlessly pressurised by their young opponents, shows a different game developing...apart from the physical grinding that the Welsh front row endured...a valuable sign of byegone days, and useful ammo for beer talk.