By RPM wins, the top 10 listed centers average 1.6 on ORPM estimate and 2.9 on DRPM. The second 10 average -0.6 on ORPM and 2.7 on DRPM. 89% of the total between tiers difference is on ORPM. The second tier plays 5 less games and almost 5 less minutes per game.
In picking a team's top center, it appears getting positive offensive impact is probably more rare and more important. Getting someone who is durable, energetic and the coach will play is also important. The second tier is still valuable and primarily because of estimated defesnive impact.
By RPM wins, the top 10 listed power forwards average 1.2 on ORPM and 2.3 on DRPM. The second 10 average 0.2 on ORPM and 1.4 on DRPM. 55% of the total between tiers difference is on ORPM. The second tier plays 10 less games and almost 8 less minutes per game, though largely due to 2 players in this tier.
In picking a team's top power forward, it appears offense and defense are almost equally important. Getting someone who is durable, energetic and the coach will play is also important. The second tier is still valuable but on average less so than second tier centers.
The market has paid the second tier centers more than second tier power forwards (I believe) and is on average right to do so, but maybe not by as much as it does. The market has played most of the top 10 at each position at or near the max with a couple of exceptions (mostly at PF) who were weaker than average on estimated offensive impact.
Second tier players at these positions are a reasonable goal / expectation by teams, though 1/3rd will not get one. Getting a top tier guy is a goal here or any position but the difference between top and second tier may vary by position in estimated impact and cost. How much could be found by doing the other positions and studying salary more carefully.
At small forward the difference between first and second tier is more than 100% on offense. The second tier is slightly better on defense.
At shooting guard the difference between first and second tier is almost 2/3rds on offense.
At point guard the difference between first and second tier is the largest of any position and is more than 100% on offense.
The difference between first and second tier from largest to smallest is PG 2.7, C 2.5, SG 2.0, PF 2.0, SF 1.6.
Given the difficulty of paying more than 2 superstars, it would appear that spending on a superstar center and point guard would have the most benefit over the second tier alternatives. Which teams does that best describe? Raptors, last season's Celtics, this season's Jazz, this season's Blazers.
Looking at 3rd and 4th tier options would be a next step.
If teams don't give weight to RPM estimates, they probably weight offense even more. That and / or misjudge defense.
Differences between 1st and 2nd tiers by positon
Re: Differences between 1st and 2nd tiers by positon
What kind of minutes cut-off did you set here?
Re: Differences between 1st and 2nd tiers by positon
I didn't have a minutes cutoff. I went by top on RPM wins. Minutes are part of that. There were a few on the low end. This was a quick and simple analysis. Could be altered. But I haven't seen similar.