So now I'm the one with the problem?
I think it is totally naive to look at her situation in a vacuum. You really think that her mess is not going to become my mess at some point? Do you really think that my wife will be able to watch her mom eat cat food without the slightest tinge of pity and compassion when we "selfishly" enjoy our high income or comfortable retirement? Could you? I know for sure that MIL's mess will become my mess sooner or later. My goal is to make it later (and cheaper)...
I guess you are referring to my post, but yes, to me it looks like you are making this your problem (which is understandable, I just don't think it is really helpful). Time for "tough love", IMO.
It's not looking at it in a vacuum - just the opposite, I am looking at it with the benefit of a little distance and perspective. I understand that you will help your MIL so she is not eating cat food in her old age. But (as you seem to be aware), the best way to assure that is to get her to cut back her spending NOW.
And it sounds like asking her to cut back NOW isn't working too well. So all I'm saying is lay out the consequences to her factually, not emotionally. Show her that the best way to assure that you can help her later, is for her to help herself now, by cutting back.
It is a tough situation, and emotionally draining, I'm sure. You are fortunate that your wife is on board with you, it would be impossible w/o that. I have the opposite problem with my Mom, I sometimes have to encourage her to spend on herself. Not such a tough problem as yours.
You know, the answer is right in your post I quoted. There is only one solution:
1) You don't want to see your MIL destitute.
2) She is spending beyond her means (leading to #1).
3) You (understandably), don't want to make too much of a sacrifice in your own life-style, to support her excessive current spending.
All very reasonable, and the answer (which you seem to be aware of), is she needs to cut back her spending NOW. There is no "try" only "do". Otherwise, you end up at the bad side of #1 or #3.
Do you see any other way for it to play out?
-ERD50