IMAP is an incredibly simple protocol compared to the sum of all the protocols that are needed to implement a web browser.
A web browser also has to be way more performant.
Both an IMAP client and a web browser have to be reliable and secure. However achieving so in a system as complex as a web browser is incredibly expensive.
Web browsers are almost as complex as operating systems.
Complexity, performance, reliability and security on that level are expensive. You would be delusional to think a web browser should be worth as much as an IMAP client.
IMAP is an incredibly simple protocol compared to the sum of all the protocols that are needed to implement a web browser.
A web browser also has to be way more performant.
Both an IMAP client and a web browser have to be reliable and secure. However achieving so in a system as complex as a web browser is incredibly expensive.
Web browsers are almost as complex as operating systems.
Complexity, performance, reliability and security on that level are expensive. You would be delusional to think a web browser should be worth as much as an IMAP client.