> I may be way off here but my observation is that chips that are very configurable are the hardest to purchase. For example, the STM32 series have something li

> I may be way off here but my observation is that chips that are very configurable are the hardest to purchase. For example, the STM32 series have something like ~3000 SKUs ( https://www.digikey.com/en/products/filter/embedded-microcon https://www.digikey.com/en/products/filter/embedded-microcon... ). Digi-Key is great for prototyping and small-scale production runs, but once you get into mass manufacturing your CM (contract manufacturer) is buying these parts for you through more direct channels. STM can produce small numbers of the various different SKUs and send them off to stocking distributors like Digi-Key to support small-scale prototyping and smaller production runs, but they don't aim to stock everything in high quantities everywhere. Unfortunately, when supply chains get tight the smallest players suffer the most. The big manufacturers went out and locked up their supply contracts when this all started. Companies like STM don't mind because it's much easier to do big manufacturing runs for a few customers than to try cater to small orders all over the place. Of course, they'd prefer to have the capacity to serve everyone and sell as many chips as possible, but obviously we're bottlenecked on the production side relative to all of the demand.