The caveat is that because MCUs are not standardized you frequently get screwed over so my replacement part list is a collection of versions of the part with different amounts of memory that are designed to be pin-compatible. Sometimes that isn't enough, and often companies aren't big enough to negotiate a guaranteed supply. But if you're not big enough to negotiate a guaranteed supply you just have to deal with buying enough of the parts to keep you in business long enough to create a new revision before you literally run out of stuff to sell...
I sympathize with the other comment berating me at length for being flippant about this, and am genuinely sorry for being flippant especially in light of their experience with the opposite issue (buying stuff and getting screwed by customers canceling orders). But I was talking about a dog washing startup. A dog washing startup vocally complaining to the news about needing to respin one board because of a supply chain interruption.
Yes, there is FCC and other testing you have to do if you significantly modify a board, so I'm not sitting here oblivious to the challenges involved in a respin. My response was to them being a poster child for the people suffering from this issue. Those of you who cannot find any component that will do the job have my absolute sympathy and I apologize for not being more verbose.
What you are suggesting is quite impractical, unless you are a really big business with cash, which can simply direct order components.
Small businesses, even in Shenzhen, a place inundated with supply chain abundance, always have to either keep running from one small wholesaler, to another searching for components, or pay n-times the price working with somebody like Arrow.
In my experience, you can't safeguard yourself against such things as a small company no matter what.
I worked in, and around OEM electronics since 2007, and things like having to redesign a product 4 times a year to accommodate a supply chain disruption were happening even in the best years. Nothing special with the current disruption besides the scale.
This is also the reason why Asian electronics makers have such short product lifetimes. It's usually easier just to sunset a product, and make an improved, and better version with newer components, than to fight against the always evolving supply chain. And I not talking about small companies, ASUS, Acer, MSI, and such all practice this.
I know few people running the Chuwi brand. What they do as a small maker is that the moment the get a good consignment of chipsets, and other parts, they spin a laptop model solely for that batch alone.
Then, they live off it until they get another good parts purchase, when they usually sell their component leftovers, or do few final runs if they can find people wanting to buy them for rebadging.
The entirety of small volume laptop industry spins around chipsets, and screens — hardest things to find for a small company.
I want you people to take a looks on a big difference in how companies in the West, and here handle the crisis: Western brands wail, cry, and wait for component supplies to resume, while Asian brands just keep releasing new products with parts coming into their hands, and making great cash from this shortage.