I don't disagree for a second there are some banks and credit unions that intend to service their mortgages but you don't know that will always be so. That's their policy now but it can change in the future and you have no control over it. Banks and credit unions are being bought and sold all the time.

The bank that held my parents mortgage was acquired no less than four times between 1996-2012. In 2007 I got a credit card from my local credit union - right now it's being transitioned into a Bank of America credit card. The credit union still exists though, they sold their credit card division to another company which then was acquired by BoA. Funny thing is a several years after they sold their credit cards they decided to offer them again and create new ones.

Exactly. My primary credit union, First Tech, also states that they will service the mortgages they originate.

What happens when First Tech gets bought out by [mega credit union] though?

First Tech bought out the HP Credit Union (Addison Avenue) and others so in some sense, it has acted as [mega credit union].

Beyond that, this question is an imponderable for me because who can say what the future brings vs. the present. I guess one can refinance with some other credit union were this to happen in the future in a manner that was not desirable for one's mortgage.