What is the point: The fact that more Americans think that Trump will ultimately be an unsuccessful president instead of believing he will succeed, makes sense. The margin of 18 points in that line is almost perfectly aligned with its net approval rating of -22 points (approval rating minus disapproval rating) in the same survey.
What is remarkable is how many people have already decided that Trump has not succeeded. The 47% who said that basically says that not only do they not like the President now, but there are also many chances that he never likes them. It gives Trump very little room for maneuver when trying to raise his low approval rating before his re-election.
Last year, the gap between success and failure was the same as now (18 points). The overall percentage of who thought Trump would not succeed, however, was 6 points lower, with 41%. That is to say, Trump had more space to grow in the past. Now, people are settling their opinions of the President.
The lack of indecisive people in Trump is truly unusual. The other three presidents on whom this question was asked led to much higher percentages of "too early to know" than Trump. At this time of their presidencies, between 43% and 47% of Americans said it was too early to know if the president would succeed. Trump, with 23%, is 20 points below the bottom of this range.
More surprising is what we see when we examine all the times that Pew has asked this question. Even at the end of the last two terms of the last three presidents, at least 26% of Americans still said it was too early to say whether those presidents would succeed. In other words, people are more locked in their opinions of Trump now than at the end of the second terms of the last three presidents. The 47% who say that the Trump presidency will not succeed is also higher than ever measured at any time in any term in the last 25 years for any president.
The only good news for Trump in this data is that we are still almost two years away from the 2020 elections. The Pew survey is not a guarantee that the President will not achieve a significant increase in his approval rating. It probably means that Trump is going to have more difficulties than we might think to become more popular based solely on his approval rating.