Not to mention the energy supply chain. If the supply chain required to make electronics collapses, that probably also means the energy supply chain has collapsed, or has at least been severely disrupted. That seems far more likely to be damaging and far more quickly that a lack of ability to keep a microcontroller running. If I don't have gas for my car, it doesn't really matter if I can fix it when it breaks down. (And I run out of gas in a few hundred miles, but repairs are required on the order of tens of thousands of miles.)
This is really what I was trying to get it with my first comment. The problems presented by a lack of ability to make new technology are the sorts of problems that take months or years to become critical, but in a true collapse setting, the issues that matter most would unfold in days or weeks.
(I feel like I should point out that I don't think any of this is particularly likely.)
