It's hard to say. As a former Iowan who has caucused, I'm not surprised by the low turnout. You have to be pretty committed to go to an event that will last several hours rather than just duck into a polling place to vote. So turnout percentages are always low for the caucuses.
But that doesn't mean the people who go don't share the views of their neighbors.
Still, 51% is not a blow out. You're right, of course.
I'm just pretty concerned because polls had been showing Trump at above 40% and less than 50%. So he did better than expected, which is pretty concerning.
I had hoped Haley would do better, not because I like her, but because significant percentages of her supporters in Iowa say they will not vote for Trump in the general election.
But DeSantis supporters almost certainly will vote for Trump in the general election, and DeSantis did about as well as Haley did in the caucuses.