I would love for someone to answer the question instead of posting gifs? If a defensive stopper cannot be counted on to stop or even slow down a hot player on the opposing team, what value does he actually have?
Last time I'll explain this but...
What was and is called hand checking was allowed. It allowed the defender to be more physical.
Tony Allen, aka the Kobe stopper? Yeah, he got away with a lot of fouls that wouldn't fly in today's NBA. As much as we love him, he fouled a lot, but refs respected him, and he rarely had a reputation of arguing/being emotional. (Smart has a tendency to be very aggressive when he disagrees with calls.)
For decades, the NBA required teams to play 1 on 1 to man to man defense. It meant everyone could guard someone. You could double team one player and then recover to your man, but being caught guarding no one would result in illegal defense. That meant you can't stay in the paint anymore all day.
NBA tried to tweak rules to limit isos, but were never 100% able to eliminate them. When zone defenses became legal, though, it made isos much harder. The two man game, the pick and roll or pick and pop, has become much more popular than isos, simply because the defense can easily flood the side of the floor where the iso is taking place, forcing the star player to go one on three or pass the ball.
However, despite the legalities regarding the defensive rule and 3 second rule, Thibs basically engineered the ICE Strong-side overload defense. Thibs implemented a system that allowed defenders to flood the strong side of the floor, and using extra defenders to force tough long cross court passes which would allow defenses to recover when beat.
Thibs used KG/Joakim Noah to remain in the paint for 2.9 seconds, step out, and step back in to avoid the 3 defensive rule.
Thib's ICE strong-side defense has been widely accepted and used in today's NBA.
To answer your question...
When you fight through the screen, and try to go around it, generally the defender has to make the tough decision to either cut off the scorer or switch on the roller. Smart is adept at this. He knows when to switch at the right time, and when to intercept passing lanes.
Our defense is predicated on switch-ability. 2013-2016, we didn't really have the personnel to consistently switch back and forth without getting dominated having someone like Avery Bradley on LeBron James.
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In conclusion...
There is no such thing as a dominant defender that can shut anyone down. Great offense beats great defense. That's just how it is. That's why you see wings who can attack passing lanes, and block shots from behind after being beat to avoid fouling the shooter. Tatum is especially great at this.
Gone are the days where you could literally have exceptional solid man to man defense, because generally fouls are called more frequently to allow more points scored in the NBA to make it more 'exciting,' for recreational viewers.
Does this answer your question?..