Right; i am looking for those sort of niche specializations where people are willing to pay good money eg; Mainframes/COBOL/Specialized MCUs/Unique Product/Maintenance etc.
However finding them is not easy, would love to have some leads i.e. websites/list of companies etc.
To be a scarcity is to chase things with high specialization and a relatively small niche.
It's actually not hard to do in SW/HW per se, find a really old language/hardware and become useful in it. Mainframes come to mind.