> I plan to continue paying 2k / month for the next 22 years there's no point paying it off early.

Why? There's some good reasons to pay off a mortgage early:

1. You pay less interest, so you pay less in total. Don't worry about the tax rebate; it's only giving you back maybe 10% of your payments.

2. A mortgage is a loan. Fewer loans means less risk. Your house can't be foreclosed on if it doesn't have a mortgage.

3. Afterwards, you have an extra $2,000 every month, because you're not sending it to the bank. Your expenses (burn rate) goes down, so your savings will last longer if you lose your job.

Not op. There are also good reasons to donate money today instead of tomorrow. Positive change in the world can also accumulate interest of time, and problems can also get worse over time

Let's say they'd have to shell out $400k to pay off the mortgage. Their $2000/month payment would be gone, but if we assume an average of 6-8% ROI on the $400k, they are missing out on a return of $2000-$2600/month. 20 years from now, the $400k becomes $1.282.000. Minus taxes.

ROI or opportunity cost. I can continue to pay 3-4% on a few hundred thousand for a few decades. Meanwhile I have a few hundred thousand “cash in hand” that I can allocate to other assets/investments. I’m betting that my other investments will return more than my 3-4% cost. And since we’re talking decades I can choose when to unwind this allocation. As I near retirement then yes, I expect to pay off the mortgage just like I’ll move out of broad equities and in to bonds and dividend focused equities.