Other than tax free compounding, for which I will pay in labor, what am I missing?

The compounding can add up. Even after you're on Medicare, the HSA remains available and will continue to accumulate (or shrink) along with the market. It still can be used on those major expenses that Medicare and whatever additional insurance you might decide to have doesn't cover.

Regarding simplifying, I assume DH is no longer employed by the company with which he has his 401(k). That can be rolled into his TIRA, and if that 401(k) includes a Roth 401(k), that can be rolled into his Roth.

In our case, my wife has the HSA, a TIRA into which she rolled her 401(k), and an IRA, into which she rolled her Roth 401(k). I have a TIRA into which I rolled my 401(k) and a Roth (no Roth 401(k) when I retired). We have a single taxable Joint brokerage account (Schwab) and a separate taxable mutual fund account with Fidelity.

Fewer accounts than yours, but Quicken makes it all easy to manage. There are other packages on the market besides Quicken.

Eric Hines