Leaving aside the internal economic problems associated with signature campaigns, I'd like to point out that mixers are destined to disappear in the future, to be replaced by non-custodial coinjoin wallets.
(Source: myself, I come from the year 3030)
This shift is driven by the growing demand for enhanced privacy and security in cryptocurrency transactions. Non-custodial coinjoin wallets offer users the ability to blend their transactions with others, providing anonymity without relinquishing control of their funds to a third party. This evolution in digital currency management reflects the ongoing trend towards decentralized, user-controlled financial solutions, addressing many of the concerns currently associated with mixers.