For most tax purposes, all traditional IRAs are lumped together into a single total. So segregating nondeductible contributions into a separate IRA doesn't simplify taxes. You're nontaxable fraction of an IRA distribution, as calculated on
Form 8606 is:
total of all nondeductible contributions across all trad IRAs / total value of all trad IRAs
There is a rational desire not to "
eat into principal". You don't want to deplete your assets that generate future dividends and growth. That said, it should make no difference whether you harvest your profits (while leaving principal untouched) in the form of interest, dividends, or capital gains.
Own a bond, and you get interest while the principal remains intact (though shrinking in real value).
Own a bond fund, and you get that same interest, but for legal reasons payments are called "dividends".
Own a stock, and you get cash dividends while keeping the same number of shares (which may go up or down in value).
Own a stock fund, and you those cash dividends passed through to you as fund dividends.
Buy 100 shares of a stock @$20 ($2000 principal), sell 20 shares when it goes up to $2
5, and you've got $100 in cap gains and also your original principal (80 shares @$2
5).
If that stock is in a fund and the manager sells those 20 shares, you get the $100 cap gains in the form of a fund "dividend", and your fund shares are worth what you paid for them (no change in principal).
If the fund manager doesn't sell and distribute the profits, then the fund shares go up 2
5%. You sell 20% of your fund shares, get the same $100 capital gain, and your remaining fund shares are still worth what you paid originally (no change in principal).
All of these retain your principal investment - whether you get interest, dividends, cap gains dividends, or take capital gains yourself. Yet somehow it feels different when the fund manager sells a stock (generating a cap gains div) vs. when you sell a fund share yourself.
I'm guessing that therein lies the source of differing perspectives.