For large gains, the US federal tax rate is 23.8% (for long-term gains), which brings the combined federal/state rate to about 30% for many investors. But the exact tax rate is immaterial to the basic argument against triggering a capital gain: The tax you pay reduces your asset base from which future investment returns accrue, so deferring the tax as long as possible is the mathematically proper (in)action.
…better alternative that I have followed last few years has been to use my Roth IRA to grow my portfolio.
Well done; however, many investors invest more money in “growth” stocks than their IRAs (and other tax-exempt accounts) will accommodate.
“The efficient-market hypothesis may be the foremost piece of B.S. ever promulgated in any area of human knowledge!”