The phrase "a mainstream area" is correct and usable in written English.
It can be used to refer to a field, topic, or location that is widely accepted or popular among the general public.
Example: "The festival showcased a variety of artists, but the most popular performances were in a mainstream area of music, appealing to a broad audience."
Alternatives: "a popular sector" or "a conventional field".
It is becoming a vocation and a mainstream area of inquiry.
"We have a strong belief that it can and it will, driven by consumer trends, become a mainstream area".
Of course you have a mainstream area and a more leftfield area, but even those lines are becoming slightly thinner".
He said he was very proud of helping to make end-of-life care a mainstream area of healthcare.
Was there any backlash from your professors and colleagues when you chose to pursue SETI rather than a more mainstream area within astronomy or engineering?
Professor Giovanni L. Sicuranza belongs to a distinguished group of pioneers who understood the potential and the wide domain of applications of nonlinear digital signal processing and was instrumental through his activities in developing the discipline as a mainstream research area.
We believe this study lays the foundation to establish women's health as a mainstream investment area for manufacturing companies, and a valuable way to demonstrate to their customers, the world's biggest international brands, that they are serious about fair labor practices and a highly productive workforce.
Epigenetics is now accepted as mainstream area of cancer research.
Imagine Mr Fox as an ambitious senator with wealthy friends, a strong interest in mainstream areas of foreign policy (relations with Israel, defending NATO) a more obscure speciality interest (Sri Lanka) and his own political action committee.
Tracker polls show consistently that the environment is a priority issue only for a small minority (around 8%), with the more "mainstream" areas like health, education, crime, immigration and now of course, the economy coming first for most people.
And other top departments now lack experts in mainstream areas such as empirical microeconomics and quantitative economic history.
