> but when we're talking about actually developing products and shipping millions of units on tight budgets with high constraints, that need to operate flawless

> but when we're talking about actually developing products and shipping millions of units on tight budgets with high constraints, that need to operate flawlessly for decades in harsh environments, you'll realize why using "ye olde faithful" 30 year old AVR core, could make a lot more technical, business and financial sense than the newest shiny ARM based chips that just came out in <current_year>. I've found the opposite to be true being a embedded engineer. AVRs in products typically smack of the Arduino->product pipeline and don't otherwise make much sense these days in professional circles. Their BoM cost is absurd versus the other options. That's why digikey still has thousands of avrs available, but stm32fs are still in the months of lead time or qty 25 from some sketchy resellers. It's pretty hard to justify an AVR is a design review either at the ~$3 qty 1 space where you can instead have a 100mhz arm with more peripherals that might allow more consolidation of your design, or in the lower ends where there are cheaper micros when you're just babysitting one or two slow peripherals.