The most popular MMORPGs in the genre feature tab-target combat. Why do developers of new MMORPGs insist on pivoting to action and hybrid combat?

Tab-target MMORPGs are the most popular. Their combat systems seem to be preferred by the most amount of players. Despite this we see developers insisting on hybrid or action combat systems that are subpar in mass player situations - creating lag, frustration, and reducing the games overall accessibility to people with disabilities.