Privacy is a public good. The iron rule of economics is that public goods are undersupplied by free markets. If only a small number of users use privacy-preserving technologies, the use of those technologies will become stigmatizing. Compare WhatsApp, which makes E2E encryption ubiquitous and normal, to Monero, which is similarly private but instantly flagged as suspicious.
Source: https://www.coindesk.com/layer2/privacyweek/2022/01/28/4-reasons-privacy-coins-havent-taken-off/