It did happen already because cryptos are finally there but I think cryptos are not invented for this (to dodge the tax system) but there might be other reasons. Many people especially those who want to avoid tax and as well as those criminals who want to launder money are now being involved in cryptos. Not to be selfish but sometimes it's good to not pay tax than the tax will just go on the wrong hands because in our modern world today, corruption are now very rampant.
There are those who are not corrupt but the other problem is the lazy people that only depend on the government to provide their basic needs. It's a kind of abusive.
Indeed I also don’t think it’s intention of Bitcoin to avoid taxes but it is created to remove central authority over the payment system. Removing authority implies a more direct contact between people interacting financially. Therefore an impact (applied by central organs) on tax collection seems logic.