Once Your Time and Money Are Gone, They're GONE
Those years, added together, are how long you take the risk and work for the IRS. After you pay your transaction tax and the market goes down, none of that new loss can apply against the gain you already paid tax on.
You owe it to yourself to explore every option. By deferring the taxes you can reinvest 100% of your dollars and double your money in half the time.