Comments, mostly in response to CD's points, above:
Of course, what matters in the long run is what the two players' careers look like - not what they look like through 2019. Fans, however, tend to be impatient, tend to care a lot more about "now" than about the long run. (Could substitute "people" for "fans" in the last sentence there...)
It only seems that way. There are 30 clubs out there, and there are several who have landed players who, expected or not, turned out great. But that's looking only at a few years. How quickly we forget Chase Utley? Ryan Howard? Scott Rolen? Jimmy Rollins?
I think CD is projecting his own view here on "all" of us. I certainly never thought Moniak, Gowdy, and Stobbe would become a "Three Musketeers," whatever that actually means. I wasn't aware that they were high school teammates (or opponents) at all. And last time I checked, I'm part of "all of us" here. "we all thought" should probably be replaced with "I thought."
Yeah. A significant percentage of Phillies phans never accepted Pat Burrell as a reasonable return on a #1 pick overall, either. Of course, that says a lot more about those phans than it does about Burrell. (Not that I'm comparing Moniak to Burrell, so don't bother trying to rebut that! The point here is that phan dissatisfaction isn't necessarily related to reality.)
No, obviously they would not. But... four years from now?
The Phillies chose to take a high school player at 1:1, in a draft where there were no really standout high school kids to draft. (Nobody, but nobody, expected Moniak, or any other high school kid that year, to be a Bryce Harper.) That may well have been a wrong choice - not that they chose Moniak in particular, but that they chose a high school player (by definition something of a development prospect) over a college junior, in a draft with no slam-dunk 1:1. It's almost inevitable that a college junior of similar ceiling/projection would reach the majors sooner - and would look like a better pick three years down the road.
All that said, what really matters is what happens long-term...particularly since we're talking about a draft pick that was explicitly a long-term choice (you don't draft a HS hitter for a short-term benefit, unless you have a crack at somebody like Harper - which the Phillies did not, in 2016). And we simply do not know - and really cannot project very well - whether Moniak, or Senzel, or some other 1st round draftee from 2016 (Puk, somebody else) will have the best career.
I appreciate that some fans are frustrated that Moniak is doing... OK... in AA, and Senzel is in the majors. I get that... but it really seems premature to me - that fans are allowing their desires, their wants, to get in the way of reason.
Now, one can certainly question whether it's wise, in general, to invest very high draft picks on high school hitters - again, unless we're talking about a "generational talent," which nobody saw in Moniak. It may be that it just doesn't make sense to expend a high pick on a high school hitter, unless you believe that kid is one of those few who will hit the majors at age 20 or so (and there were no high school hitters in the 2016 draft in that category - and only one first-round HS pick who's not a pitcher who has seen the majors - Carter Kieboom, who was awful in a few games for the Nats in April/May).
It appears that the Phillies have revised their approach since 2016 - Haseley, Bohm, Stott are all college hitters, all far more advanced as hitters than Moniak when drafted - and interestingly, all older today than Moniak (even Stott, drafted three years later, is seven months older than Moniak).
But the Phils opted for the long-term investment in 2016 - and because it is a long-term investment, it's kind of pointless, IMHO, to try to evaluate its performance in the short term.