The most common retirement strategy advisors still give today is "buy a good index mutual fund and hold it forever." That aged approach has been around since I got my start in the markets in the mid-1980s.
Sure, buy and hold is the easiest strategy for a client to follow. After selecting a fund, there is nothing more to do.
That's why it's great for advisors and mutual funds. Keeping your money is their top priority because they get paid based on assets under management, not performance. Plus, redemptions cost funds money and time. For every "sale," they have to deal with paperwork and transaction costs when they sell shares to raise cash for the redemption.