The Future of Bitcoin Privacy: Cross-Input Signature Aggregation. Bitcoin Tech Talk Issue #216
Privacy is something everyone talks about but few people actually take time to do properly. This is as true in life as it is in Bitcoin. Coinjoins are not a great user experience right now. Not only are the anonymity sets small, but the process itself takes a long time and costs money, which motivates people to not do it. Not enough people custody their own coins, and even fewer have the technical knowledge to actually coinjoin in one of the many protocols.
The problem, like with most privacy tech, is that it costs a non-negligible amount of time and money. This can be a problem in an increasingly authoritarian world that demands permission to do even the most basic things. Many places transmitting or handling money must comply with AML/KYC laws, which are a giant tax on these companies. CoinJoin isn’t quite that bad, but it’s still not easy and most people simply don’t bother with it.