Do ETFs really generate fewer taxable capital gains distributions than mutual funds?

Generally yes, and it's one of the strongest tax reasons to prefer ETFs in a taxable account. Mutual funds must sell holdings to meet redemptions and to rebalance, and they distribute the resulting capital gains to all shareholders, so you can owe tax on gains you never chose to realize, sometimes even in a year the fund lost value. ETFs use an 'in-kind' creation and redemption mechanism that lets them shed appreciated shares without triggering taxable sales, so they rarely pass through capital gains distributions. You still owe tax on dividends and on your own gains when you sell, but the surprise year-end capital gains distributions common to mutual funds are largely avoided. In tax-advantaged accounts this ETF advantage doesn't matter.