I guess my question here is - why is that the only thing that we can do? There really is no requirement to use grades, and no way that they can be forced upon anybody, all that it requires is for people to decide that they no longer want to go along with a system with so many negatives and so few positives.
It could happen - and I think it will happen at some point.
I wouldn't mind.
I'm reminded, though, of what a high Japanese kendo official told me happened when they decided to drop the 9th dan and settle for "only" eight dan grades. Some old 9 dans sent their diplomas back in recognition of the new rule - and some didn't.
If the people who don't care about grades drop them, only the ones who do care will advance in grades - and claim loudly that it means something. Some things, once introduced, are very hard to get rid of.
Anyway, if treated in a relaxed and proper manner, grades don't need to be much of a threat to aikido.