Larry definitely put in the time to learn the match up. Not only did he laser the Can to disrupt it, but he recognized Duck Hunt's "eye of the storm", where there's a brief pause inbetween things like Gunmen or how you can run under Can if it's pinged too high.
I'm very, very glad people are catching on, as I believe that although counter play will hinder Raito's success, I think that he is a huge victim to autopilot and playing his own game, so I'm very excited to see him push his game a thousand percent. We've seen it today where he played stellar VS Tweek's Bayo. Once he's faced with adversity, he puts in the time and it definitely pays off.
In fact, even with the counterplay, you could see Raito piece together everything as the set progressed. The only game he got blown up, if I recall correctly, was the first one, as Larry's drastic change in playstyle caught him off guard. Towards the last 2 games, you saw Raito giving him a run for his money.
Also, fun fact, Larry is a genius and has demonstrated ZeRo-levels of counterplay: Remember the situation where Raito won the game while him and Larry were near the ledge? Remember when D1 said "He jabbed the wrong way"? Had Larry got those jabs, it would've frozen Can for a second, allowing Larry to Up Smash without fear of Can interrupting. It was at a spacing where Can wouldn't have hit Duck Hunt. I was extremely impressed by this detail that very few would've been able to catch.