Yes, but they had no choice did they? They were replacing 377s and had to be brought up to a higher standard. They probably wanted new rolling stock and were told that this is what they were going to get.
I doubt FCC or the next franchise holder would have any desire or requirement to do anything like that and would argue that an all-new fleet would be more economical.
I would be quite happy to see 313s stay in operation if they were given a proper and radical refurbishment. Actually, given more trains are now running as 6-cars, I'd even suggest that at the very least they change the seating to 2+2. In the peaks, they'll allow more standing (and easier boarding/alighting as the 3+2 makes it near impossible to move down the aisle to get off if it's full) and off-peak the trains are actually almost empty so even a quarter of the seats would suffice!
Those who travel from the furthest out to come into London during the peak would get a seat anyway, those boarding later on would likely stand but not have very long to be on the train in comparison (15-20 minutes?).