Maybe I just have more gold than most, but the repair bill from deaths doesn't even come close to what I pull in from drops. Granted I do the chest/goblin/etc runs, but if I had the DPS for champ runs, I can't imagine the bills piling up so high that it would be worth it to me to sacrifice DPS for "survivability".
Well no, if it did you wouldn't be doing it, right? Besides the fact that we'll be spending probably 5x as much on repairs, though, these deaths eat up a lot of time, as does the tactics sometimes required to kill champs (i.e. you are kiting three times as much as necessary because you can't afford to take even trivial damage). When survivability stats actually start working as a buffer not just against death but allowing you to mitigate that lost time that piles up, it starts to become pretty attractive. The only reason this strategy is actually prominent rather than just viable is because that trade-off isn't working efficiently specifically in regards to time. Part of the reason enemy health is going down along with enemy damage output is specifically to reduce the value of your damage output along with increasing the value of your TTL via their damage output nerf.