That same flawed theory every day - you need physique, muscle & power to hit SIX. Yes, you need those to hit six from mistimed shots, edges and unorthodox reverse flicks.
To hit a six properly, you need timing, foot work to reach the ball & connect it on the rise (by physics, a projectile will travel longest if it’s released at 45 degree, so ideally at the point of contact with bat, a ball will travel longest if the entrée & exit trajectory crests a 90 degree angle with the bat), transfer of body weight (from lower trunk to upper trunk), bat swing & coordination of body swing with bat swing (batting is a side on game - while hitting a six, power combined from bat swing from back lift and body swing at waste line). These are batting skills, not power. Our Mushi is 5’3” (now 5’2” after losing hair) and 130kg max - he has like 170 international SIX, close to 100 in ODI - longest one being 107 metres.
Once again - SIX hitting is a batting skill based on technique, not from power. Obviously someone 6’3” and 200lbs will find it easier to hit a six over someone 5’2” & 130lbs with COMPARABLY equal batting skills.