For backgrounds, it's not a bad idea to stretch imagery with the browser, as you can maximize the impact of the imagery, however for text, having it scale out in a fluid manner to 2560 is not a good idea.
An example: http://thegreatdiscontent.com/
Their background image scales to the full width of the browser, which will look great on larger screens.
However, if you scroll down you can see their text remains at a fixed width. Imagine if the text stretched all the way to 2560, the number of characters per line would make the text difficult to read. The eye would have to trace a long line all the way back from the end of the line to the next line, and this makes it easy to lose the line you are currently reading.
From the Baymard Institute:
The optimal line length for your body text is considered to be 50-60
characters per line, including spaces (“Typographie”, E. Ruder). Other
sources suggest that up to 75 characters is acceptable.
So what’s the downsides of violating this range?
Too long – if a line of text is too long the visitor’s eye will have a
hard time focusing on the text. This is because the length makes it
difficult to get an idea of where the line starts and ends.
Furthermore it can be difficult to continue from the correct line in
large blocks of text.
If you are really set on making your site fluid for all screen sizes, you could consider scaling up your font size as the browser width gets larger so that you can keep the number of characters in a column to an acceptable number.