We as a species make up terms on a daily basis, so I feel the liberty to do the same. Glad it doesnt give any results because it indicates original thought.
If large parts of the supply chain consist of suppliers (vendors) on the other side of the earth, one can focus on one vendor lock-in or one by one (for analytical purposes) and optimise for that but often the bigger picture of a complex supply chain is missed.
Hence the aggregated lock-in.
But to avoid futher confusion maybe supply-chain lock-in is a better term and yields searchs results.
Only thing I claimed was you missed the point of SomeAmateur, meaning one can understand global supply chain AND worry about depending on foreign entities using it in geo-politics, so mentioning counter measures (make some stuff ourselves for a change) is reasonable.
I am wrong all the time by the way, I just adress a lot more in my comments which you choose to ignore.
But alas, you are free to pick and choose just like everybody else.
Supply chains are literally chains of suppliers, e.g. vendors. Your 'simplest electronic product' could absolutely be constrained by whom you choose to work with.
If your vendor locks you into buying from a certain source, and their vendor requires the same, and so on up the chain, how would you describe that dynamic to differentiate from a single vendor being the point of restriction?
To your point that the phrase didn't exist, here are three supply-chain oriented papers that directly reference the phrase:
This paper is exploring the social dynamics of buyers and sellers:
Specifically, we believe that the examination of lock-in situations between a manufacturer and its supplier, i.e., instances where for all intent and purposes, one party is heavily dependent upon the other party, with few alternatives, under social exchange theory, can provide new insights into controlled self-interest behaviors (e.g., strategies) in on-going supply chain relationships.
This paper is about supply chains in plastic management, but the phrase is here:
Supply chain lock-in:
Contracts and strong dependencies with suppliers not supporting circularity (e.g., either due to non-willingness or lock-in in production facilities optimized for linear concepts).