As far as I know there is no way to stop etching except hand washing them. I buy break resistant dishes and my glasses lasted at least 15 years and they were etched. When I found more break resistant glasses I replaced them.

I would look into your water softner. Did they test the water for you and recommend what it would take to really soften it? I had an etching problem and read up all I could about it. Once they are etched, it's over for that glass. I got new glasses and started using Cascade complete and plenty of rinse stuff. I try to avoid the lemon versions. I cut down on the amount of detergent I was using. I ran vinegar through the dishwasher every month. Seemed to help.

We could not afford a water softner, but after replacing the dishwasher in less than five years, and the hot water heater, we know we should have done it. Done correctly and maintained correctly, a softner should not leave water etching your glasses.

We are moving to a new home in a rural area; we will have whole-house rainwater collection for our water. They say it is naturally soft and won't harm your appliances...or glasses. If it rains.