By that time they had clearly made the decision to invest in their own CPUs and platform architecture.
So what you're telling me is that Apple is willing to put multiple generations of devices out to pasture because in the future they intend fix it with a new platform. That does not inspire confidence that they now care about thermals, the opposite actually. What you're saying is that they again might have slipped up and we need to wait for the next redesign for it to improve.
More: Apple makes long-term investments and big technology bets.
They placed a large bet for the MacBook on Intel’s roadmap at exactly the wrong time, and it screwed up multiple product planning and execution generations as a result.
Apple has finely tuned their organization to be great at long-term plans. That has come at the cost of being able to adjust “quickly” when those plans end up being flawed. The fiasco with the butterfly keyboard is maybe the best example.