That’s absurd. The heavier the bat, the more mass you hit the ball with. There’s a tradeoff between mass and speed, which is why major league ballplayers have been using the same weight of bats for DECADES. If light = more power they’d all be using 25-ounce bats, but they’ve stayed consistently at 31-34 ounces for a long time now - Roger Maris used a 33-ounce weapon. Super heavy bats will hit the ball further still - Babe Ruth used a 40-ounce bat - but put the batter at a disadvantage against power pitchers, since you can’t hit the ball very far when it’s already in the catcher’s mitt. Average pitch speed is exceptionally high now so using a super heavy bat won’t work, even though you could crush the ball even further.
As a bat gets heavier you gain more mass, which puts more speed into the batted ball, but beyond a certain weight you begin to lose bat speed, losing ball speed. So there’s a law of diminishing returns. However, there’s also a law of diminishing returns going down; dropping a few ounces might gain you some bat speed but at the cost of mass striking the ball, and below a certain weight you really aren’t going to be able to swing the bat any faster. It’s very unlikely a strength-trained major league ballplayer isn’t swinging a 31-ounce bat with 10% less speed than a 28-ounce bat. That weight different might matter to me, though - but I’d gain little bat speed going from 28 to 25 ounces. You can only move your arms so fast.
So in truth, every batter has an ideal bat weight which maximizes his return between mass and bat speed. Lighter would not be better from that ideal weight.
The reason bats are breaking is that they’re making the handles thinner to shift more mass to the barrel, plsu there’s some reason to believe maple bats are more prone to shattering than ash bats.