Exactly. Centralized exchanges will prove to be the easiest way for governments to collect taxes from their citizens. There's no other way around it. The hardest part will be collecting taxes from decentralized exchanges and in-person trades. That's largely because these solutions don't require ID verification of any kind. A decentralized exchange that complies with KYC/AML regulations is not decentralized at all, making it possible to collect taxes from it. This alongside privacy coins like Monero, BEAM, or Grin, will make crypto taxation quite an impossible task. That's why we've seen how recently governments (especially the US) have been interested in tracking down privacy coins in their entirety. Apparently a Blockchain analytics company called "CipherTrace" has been able to track & trace Monero transactions. If their tool is as they claim it to be, then governments will be able to successfully collect taxes from Monero users.
Nonetheless, time will tell us what lies ahead with the future of crypto. If taxation becomes widely successful, then crypto/Blockchain tech will be considered as legal in the mainstream world. Otherwise, expect a massive crackdown on the entire industry. Ban or no ban, crypto will always exist thanks to its decentralized and open source nature. Just my opinion