However, Unlike public museums
Be careful not to capitalize unnecessarily. : )
At the beginning of this essay you used the term pros and cons incorrectly. When you talk about pros and cons, you are talking about advantages and disadvantages. But at the beginning of this essay you should write, nowadays some people expect that public museums and art galleries will disappear...
Public museums and galleries will be always exist as displaying art objects
needs the real place will always
be done in person and not just through digital media .
Public museums and galleries will
be always exist
as displaying and display art objects in real space rather than mere images.
: ) Your writing has great structure, and you just have a few grammar errors.