Publishing, like other businesses, is driven by profitability, and renowned journals are no exception. For those traditionally print and now optionally open access journals, the subscription is fixed and not particularly expanding in this increasingly open access environment. The open access is expanding and some. The directory of open access journals (https://doaj.org/) lists 12,166 journals; of which 9,123 are searchable at the article level. The traditionally print journals that recover their cost through subscription are almost forced to offer an optional open-access, to recover the cost and stay competitive. Plain and simple.
The other side of the coin: Given the benefit of the open access to the reader who cannot afford subscription, many organizations fund their researchers' open access publishing to help with broadening the impact of their research and helping the scientific community in dissemination of knowledge to "underserved".
Open access journals are the results of widespread use of Internet and on-line publishing. Many of these journals are available in print form too. Open access journals have several plus points: they enable free access to research papers, lower the costs for research in both public funded institutions and private concerns, and improve access to information for the public. Probably, a major advantage to the authors is higher citation rates, which will be reflected in author impact factor.
Open access is achieved in three ways. Many open access journals are made free utilizing the subsidy they get through grants from funding agencies. In such cases, neither the authors nor the readers pay any money for publishing and accessing the papers. Some open access journals do so by accepting page charges or charges per article from authors. For example, PLOS (Public Library of Science) journals demand specified fees for an article. A third method is to publish the articles in a traditional subscription based journal like Nature, and after a certain period (six months or so), make their paper freely available on the Internet by self-archiving it in their institutional repository.
Many open access journals are providing service to the society where funded by government and societal organization for the welfare of nation as a part of rendering social services
It basically a teacher for large number of fraternity across globally.. the quality and reliability of these open access is acceptable accuracy as compared to the paid journals