Is it possible to wear out the cassette lockring threads?
Like any bolt, it  can wear down over time, even if it's being installed and removed properly.
But, the biggest issue will be with incorrect installation or removal. Main issues that will damage the lockring are:

Not inserting the tool into the lockring correctly
Using a tool which is roundered at the teeth
The threads are fine, cross-threading when installing
Over tightening - check whether the lockring is alu, if it is, it'll be weaker than a steel one
Snapping the thin washer - this washer helps protect the teeth on the smallest ring too

From proper removal and installation, it's unlikely that you will wear the lockring quicker than you wear the cassette itself. There are plenty of people who do this monthly in the summer and every 1 or 2 weeks in the winter on their bikes with an ultrasonic cleaner.
The biggest challange is making sure you don't make a mistake and damage the ring during remomal or installation. So invest in a good lockring tool and always start it by hand to avoid cross threading.