But this is precisely why there is a responsive layout - so that the page looks equally good on different devices and different screen sizes.
But I feel there is a lot of space here that can be saved.
Why are all the elements so huge? This is not a touch screen.
Why do you pay so much attention to secondary elements there (highlighted in red), dropping the main content to the bottom of the page?
Author / date creation. I wrote about the author and the date of creation here.
Follow. Forums with thousands of members and millions of posts, but several people subscribe to topics. It looks something like this:
Promote. Who sees this button? Only admins and moderators? So it only looks good to a few people on the forum, but thousands of other members see a huge empty space?
Share. Do you have statistics on the use of this button? This button is almost never used by anyone, but you have given it a central place on the page. Seriously?
Moderation Actions. Again — so it only looks good to a few people on the forum, but thousands of other members see a huge empty space?
Start new topic / Reply. I wrote about it here.
One more example on a smartphone:
It looks ugly, it duplicates the same action, it interferes with clicking the "Submit" button.