I am not so sure I am wrong in what is or isn't a taxable event. What you are describing is current situation in which many taxable events are not in the radar (that¡s the radar i am talking about) of tax office. Yes, I know you can do as you wish right now and most probably not have any tax issues, but that doesn't mean they weren't taxable events.
When we are talking about rich cyrptocurrencies people they are already cashing out some of their gains into fiat, real state, etc.... so they are already on the radar of the tax office and when you are, you better behave perfectly or you risk some HUGE fines/prison.
It's not the responsability of the exchanges to fill your tax forms. It is your responsability to identify any and all taxable events and declare them properly with or without any help of those exchanges.
Isn't tax only applicable at the point where it is realized into fiat/Gov't money? (give back to Caesar what belongs to Caesar). I think this is why Gov'ts are pooping themselves. If the most tax efficient way to live is to stay in non-gov't money then transactions will be done that way rather than using fiat wherever possible (think of the dual pricing for goods that could develop where taxing profit isn't applicable ) Gov't would do everything in its power, and some things that are not, to prevent this from happening, but they think they should be an authority on such matters where really governing and financial interests should be separate concerns (imho).
If fiat gets sucked into this system and the fiat 'money as debt' shrinks, then it would disappear eventually up its own vent hole. Voila! End of an Empire and someone else gets the reigns.