"If I were building Dish Network today, I wouldn't be investing in satellites." That was among the latest quotes of our dear Charlie a few months ago trying to "explain" his foray into Blockbuster and wireless spectrum. He is building a massive data center, according to Scott, as he has seen it himself. Considering Dish has abandoned "Tweener" sats it was so feverishly fighting for (that Spectrum 5 held among other tweener slots Dish thought it wanted), that quote says a lot.
Dish is pushing Internationals onto IPTV and currently has DishWorldIPTV in operation. 118.7 is likely the LAST EVER sat for Dish Internationals. So, one sat down. Ergan is also trying to build an Over The Top (OTT) service much like Dish Network, but via the internet (might be IPTV), and the plan is to NOT have expensive sports services for the OTT service.
The sats in use by Dish now (some owned by Dish, others by Echostar) are pretty young, along with some fresh ones on the way. We are not likely to see more than perhaps ONE COMPLETE sat failure. However, be aware that NOT every drop of bandwidth is in use on every sat, necessarily. They do have some back-up reserved on currently operation sats so that if they suffer one or multiple TRANSPONDER failures, they can move those channels to the other sats.
Also, trouble with sats such as you researched regarding Dish are NOT uncommon among other sats in use by other companies. DirecTV has its own history of failures or anomalies as do the Cable Neighborhood sats, but due to on board back-up and other clever tricks, they all keep servicing well enough, although a replacement may have to be ordered if an in orbit spare is inadequate. But in most cases, they limp along for a few years until the replacement is launched. Also, replacements are built BEFORE the 15 year life of the operating sat, often launched by the 10th year of service. So, they do try to stay ahead of the curve.
Dish is in a much better position than it was a few years ago when the constellation of sats were stretched to the limit. I wouldn't worry about failures at this point, and look for more content delivered via internet, not satellite, although sat does have some advantages, it has been clear for some years that Dish's long term plans are to most likely use the slots they own only, but that is still years down the road as encoding improves and Dish OTT from the massive data center becomes more common. They won't be leasing the next gen of sat or slots. Again, for Dish to have abandoned its plans for "Tweener" sats seems to indicate less dependency on large numbers of sats (as today's constellation is) in the fututre.