Evaluating the business viability and solvency of any important suppliers is something that you should be doing yourself even if you have a years-long contract.

Also, such risks can be insured.

Also, such risks can be mitigated in various ways - I recall having a contract where the source code of any product version delivered to us would be held in escrow at a third party, and in case the supplier went out of business or a bunch of other conditions, we'd get their code and legal rights to use/modify/maintain it ourselves or through some contractor.

A contract is between you and some entity - if you want to protect yourself against that entity "dying", then that can be done by a contract with someone else (e.g. insurer, escrow, etc) who can make you whole even if that entity is dead.