You’re not wrong there’s truth in this. But none is saying don’t know how to play in an actual game. You absolutely learn about spacing and where to attack and how to pull up and how to react to different looks by playing ones. Three dribble ones are the GOAT at progressing your individual game. That absolutely carries over to game speed
You learn aspects of it for sure. 1s teaches fundamentals on footwork, picking and attacking a spot, creating space between a defender, using that space to create optimal shot (ideally a face up), just all the basic to intermediate tools of scoring.
Fostering those skills AND THEN maintaining that high solo scoring performance in 3's and 5's ON TOP of honing spatial awareness to know when help is coming, to not be crowding another teammates space, to move without the ball, to split a double team or throw to a flashing man/cutter is where the expert level of offense starts.
You see this all the time in LA Fitness type of runs where during 5's, most runs are playing man d and nobody is playing help and you got a large percentage of guys who
look really good when theres no help defense and their teammates have cleared the paint and perimeter. But that lack of skill (and honestly, capability) in dissecting zones and knowing where your teammates are going to be when defenses shift is what separates good players from greats, just my two cents.