Nostalgia is a dangerous thing. Tackling happens plenty still, but it never has been, and never will be an easy feat in the open field, which is where the vast majority of offenses attempt to create plays now.
People made these same exact statements when Jerry Rice and the 49ers were decimating defenses all over the place in the 80s/90s… “They don’t play defense like they used to, the Steel Curtain would’ve shut this pretty boy Montana down and this Rice kid wouldn’t catch a pass!”