Can you clarify the advantages of a taxable account over a tax-sheltered account? For example, in what scenario would you invest in a taxable account over a Traditional IRA? I can see a 401k being fee dependent since you may not have access to low cost funds.
1) There is the obvious benefit of financial flexibility. You can let your tax-deferred accounts grow even larger when they are tax-deferred for longer. Or you can withdraw just enough of your IRA/401(k) to hit whatever tax bracket you choose (hint 0% or 10% is a good idea). Just use your taxable account to make up the difference.
2) But, to me, the bigger benefits come for specific purposes. An inherited stock comes with some very nice benefits. Suppose you buy stock for $1000, die when it is $8000, and your heir sells it for $10,000. How much profit is taxed assuming you don't pay the estate tax? Hint, the first $7000 is tax free and only the last $2000 is taxed. That is a nice way to give your heir $7000 profit that never gets taxed.
3) When you donate stock from a taxable account it is even better. Not only are the gains not taxed, but you also get to double-dip and deduct the gains from your taxes. The drawback is that you actually have to make a donation at least once in your life, but hopefully you are in a situation to do so.
Take the $1000 stock example that grows to $8000. You could sell that stock, and pay taxes on the $7000 gain. Assuming it was a long term investment, you usually pay 15% tax, or $1050. You net $6950 on the sale ($5950 profit after tax). Suppose you then wanted to make a generous donation of $6950 to your favorite charity. So you write a check and get a $6950 deduction. Assuming you are in the 33% income tax bracket (fed + state) that saves you up to $2293.
But, here is the benefit of a taxable account. Don't sell the $8000 of stock. Donate the stock instead. If you donate it, you never sold it, so you don't have income. You don't pay $1050 in tax. Also you get to deduct $8000 instead of $6950. Your tax deduction saves you up to $2640 in the 33% tax bracket, $346 more than if you donated cash. So, not only do you avoid tax, but you get a larger deduction. You save a net $1396 because you had it in a taxable account vs using cash for your donation. And the charity gets $1050 more!
Yes, you can donate from a tax-deferred account, but then you are losing the tax-deferral from there on out and you are limited to only a few thousand a year that you can put into the tax-deferred account. The taxable account isn't limited. So if you can avoid the tax, you get the benefits of the IRA without the limits (unless you are donating a very massive amount).
4) The long term capital gains tax rate is currently 0% if you are married filing jointly with a taxable income of under $75,300. Think about it. Keep your income to a "low" $75k and your gains are tax free.
https://www.thebalance.com/how-to-use-the-zero-percent-tax-rate-on-capital-gains-2388995