boosting got worse over time,mostly for 2 reasons:
1.player power and scaling over the lifetime of an expansion became far more extreme,in mop 1 geared player could easily do multiple times the dmg of fresh players
2.gold inflation,in wod it reached the worst case,everyone had milions with the garrison to afford buying runs,and it came at the PEAK of player power with the legendery ring 8-10 players could easily boost a full 30 man grp in hc hellfire,kinda ironic considering how pruned the classes were in wod,but that ring was just bonkers,it completly ruined hellfire as they didnt even tune the raid around it