I think that decentralized exchanges will help people to control paying taxes. BitShares DEX is an excellent example. Chines people adopted it because there you are safe and no tax collecting agency on the world can't get data about you trading as long as your account name can't be connected to you.
On BitShares there is no company or other entity behind the DEX. Tax collectors simply have no one to address its demand to him, for give personal data away.
More in my post: https://steemit.com/cryptocurriences/@tombort/why-irs-can-bust-you-on-centralized-exchanges-and-not-on-bitshares
I also wrote post about personal data safety:
https://steemit.com/cryptocurriency/@tombort/inportance-of-separating-our-personal-data-from-account-names
Please review and comment!