Here, I went and looked it up:
https://www.forbes.com/sites/jensen/.../#3efa4f983d58
"Between April 2012 and August in 2015 Subaru said it had eleven reports of vehicles stalling in the United States."
11 failures from the valve springs.
40+ failures after the recall work, on this forum alone.
The rate of successful recall work isn't relevant as far as safety goes, the comparison of the rate of failure between the valve springs and the recall work is the relevant safety metric.