Position players assigned a 70 FV go on to be more productive than pitchers assigned a 70 FV. But this covers a very small number of players.
Looking at the 65s, it looks like the pitchers go on to be more productive on average by a small amount.
Looking at the 60s, it also looks like pitchers do better by a small amount.
Then for the 55s and 50s, the hitters do better by a significant amount. A 55 pitcher is closer to a 50 hitter than a 55 hitter.
I suspect the results for the 60s and 65s are flukes due to small samples. But maybe this needs to be looked at more closely.
Most prospects are 55s and 50s. These types of results are why we saw FG unilaterally shift the grading of pitchers down half a grade, and is why Soroka suddenly went from a 60 to a 55.
This shift in grading stopped this type of mismatch from happening, which was the first kind of work done to show just how much value pitchers gave up due to risk:
https://blogs.fangraphs.com/valuing-the-2017-top-100-prospects/
This has been a gradual process to get pitchers valued roughly equal to position players. Folks who have followed along over the years have a good understanding about why pitchers have seen their overall value drop over the last 3-5 years.