In the image below, this crack was directly beneath a window. The wall did not have enough strength to hold back the force of the ground on the other side. To fix it would have required pulling out the window and pouring a new concrete sill heavily reinforced with steel, which would prevent the wall from buckling in. The cost was estimated to be as high as $5000.
In the two images below, a large crack (about 1" wide) can be seen running down the wall from the ceiling to the floor. Amazingly, the basement window is also bent, but the glass is not broken.
The image below is from the garage, where frost has made its way under the insufficiently insulated floor. It's hard to tell from the photo, but this whole section of wall is buckling inwards due to the uplift of the floor and the force of the ground on the other side of the wall pushing in. To fix it would require supporting the house above while the entire wall is ripped out and rebuilt. The cost for this repair alone was estimated at $15,000 - $20,000
It was interesting to hear from our builder some of the history of these types of cinder-block foundations. Apparently, when these houses were built in the '50s, poured concrete foundations were available, but were more expensive and required a trained crew. A builder could save some money by using cinder blocks because the blocks were cheaper than the equivalent volume of poured concrete and the builder's own workment could usually do the job.
Interestingly, today the situation is reversed and it would now cost more to build a cinder-block foundation (not that I think you ever would want to).