Buy-n-hold works great for people who truly understand the business cycles and know the companies really well. But only a small percentage of the market participants know how to estimate the "intrinsic value" of a company. Warren Buffet is a genius. But if you follow his philosophy and simply buy and hold, the outcome could be disastrous. Among the many thousand of stocks traded in the USA, most of them are good only for trading.
However, if you are an investor of a broadly diversified mutual fund, buy-n-hold strategy will probably work better over the long haul. In retirement accounts, tax is not a concern, and commissions are cheap, you can keep trading as long as the value of your account keeps going up.
There are traders and investors in the stock market. Anyone who can make money is a winner.