you're grossly underestimating the absolute ingenuity of 7-10 billion people jostling against each other for status. even if people were taxed such that net income was exactly the same for everyone, higher earners would still try to claim superior status from it.
and that theoretical limit of perfect, simultaneous, accurate information is akin to the heat death of the universe, and really not worth practical (as opposed to theoretical) discussion. for all practical purposes, at the very least there are rate limits related to the propogation of and reaction to perfect info, not to mention all the ways people will actively obstruct it.
I dunno, the status appeal of money is very much what you can buy with it.
I can technically imagine stores both online (good old tracking) and brick-and-mortar (looking at clothing and subtle body cues: inferring health, psychical well-being etc. - if not matching to external data with facial recognition) being able to quote, with machine learning, higher prices for you at check-out if your financial situation is better. Now of course wealthy people spend less on such "trivial" consumption in comparison to capital investments, but for middle class this could be significant. I mean a kind of thing like this.
the rich person would just hire poor people to buy their trivial consumption items for them, both to get better prices and to put downward pressure on the practice. that's not even a particularly ingenious solution, but that's the kind of thing i mean by underestimating our collective ingenuity.
the transactional value of money is not inconsequential, but people absolutely do all kinds of (silly) things for status (see social media), moreso than just for transactional value.
and that theoretical limit of perfect, simultaneous, accurate information is akin to the heat death of the universe, and really not worth practical (as opposed to theoretical) discussion. for all practical purposes, at the very least there are rate limits related to the propogation of and reaction to perfect info, not to mention all the ways people will actively obstruct it.