I think for the OP to make sense, they have to have been the best for three consecutive years. This immediately rules out Kiptum given the short timeframe when he was running marathons. And you can't include Kiptum, but also have Kipchoge as the best for 2022/2023/2024!
Also marathon runners don't always enter the world championships, perhaps considering it inferior to the Olympics and the majors, so it's not really a relevant comparison. It should be noted that Radcliffe did actually win the marathon world championship in 2005 though. It's also not cleat that Tergat was the best over three years.
It also makes no sense to discuss athletes before the world championship era, as with Olympics only every four years, an athlete who is consistently the best will always have periods of over three years without getting a gold. Even then, before it was every two years, sometimes there might be just one championship in a three-year period. E.g. Sergey Bubka didn't win from 1984 to 1986.
That leaves Bekele and Powell from your list. Did Bekele just not enter the 5000 in 2005 or 2007? Gebrselassie used to only enter the 10,000m (so perhaps another contender for the list), but really it's a bit of a loophole, and doesn't really have much of a bearing on the Ingebrigtsen case, because he has positively failed to win gold.
So Asafa Powell is probably the one with the fewest caveats on your list, as he probably was the best from 2005 to 2007. However, it's still worth noting that Ingebrigtsen has had three years in a row with a world/Olympic championship. Powell only had two in that period.
So perhaps a better question is: Has anyone been the best over three consecutive years and on three occasions failed to win a world or Olympic gold?
That all said, to those saying Ingebrigtsen isn't the best, it's not like there has really been another contender. Those that have taken golds have not performed consistently enough across a season to be called the overall best. Unless someone simply considers the gold-medal winner to be the best in that season, in which case this entire discussion is pointless.