Yes the F-16 radar could theoretically have spotted the C150 if the pilot had the time to share the complexity of single-seat jet high speed flying duties with added radar operation too, as well as at the same time still assuring "see and be seen",
Last time I was in the business, this was part of the job description for single-seat fighter pilot.
This was not:
all when he thought ATS was comprehensively providing separation service
But I agree to some extent here:
So the type of ADS-B needed for that C150, and everybody else in low end GA too, was a small, light, low cost unit (maybe even portable) of under $500
....and a good cheap cigar.
