Where did you find this image?

There was a thread last year on Houzz international discussing how the quality of foam has gone down, doesn't keep it's shape as well on new furniture. Better sofas can come with a warranty, have you checked yours and what it covers; eg frame only ?

It all depends on how much money you would like to spend. As your lounge is dark and your stools and bookcase are also dark I think white chairs would be fine, but then I would change the stools as well and take some white down to the lounge area. However you can buy stretchy covers for this style of chair for around $10 and there is quite a variety, so I would look on line for those to see if you like any of them as that would be a very easy fix.

Mimosa has a similar product. Without knowing the actual furniture manufacturer, mimosa may be a good alternative.