Rising prices without a corresponding rise in income isn't true inflation, it's just squeezing your people to get their juice. But it does somewhat emulate inflation.

I suspect you'll find that you always have slightly different rates of increase for different prices and different incomes. There's no such thing as perfect lockstep increase across an economy. As a result, there will always be somebody who gets hurt. In practice, those people tend to be pensioners, not the middle-aged wealthy.

It occurred to me that our fiscal an monetary systems are horribly complicated, and full of loopholes.

Yes. But that's quite hard to avoid. The world has lots of complicated corner cases that have to be handled. This goes with the territory. When we apply a tax, we generally apply it to "the market value of" an asset or a gift or what-have-you. But "market value" is an abstraction that doesn't perfectly capture the underlying reality. So there are going to be corner cases where somebody profits from the modeling error. I don't see a way to avoid this. Mitigate when possible, yes. Solve, no.