Layoffs might have to with what a person is working (project is no longer business priority, just cutting based on performance might lead to delays) or what team a person is working on (whole org gets the axe).
How is 1 false? Log improvement means for 10x the cost the model is 2x as good. For 100x the cost, the model is 3x as good.
Not a curve to be happy about TBH. You need to simultaneously find big efficiency wins and drive up costs substantially to get 4-5x improvements, and it is probably impossible to maintain good year on year improvements after the first 2-3 years when you get all the low hanging fruit.
Not sure early versions of rust is the best example of refcounting overhead. There are a bunch of tricks you can use to decrease that, and it usually doesn't make sense to invest too much time into that type of thing while there is so much flux in the language.