Just food for thought:
Summer League Year by Year Leaders
2004 Leaders
25.7 ppg Nikoloz Tskitishvili (DEN)
12.7 rpg Lonnie Jones (CLE)6.2 apg Steve Blake (WAS) and Jameer Nelson (ORL)
2005 Leaders
20.6 ppg J.R. Smith (NO)
9.8 rpg Josh Powell (DAL)6.0 apg Sebastian Telfair (POR)
2006 Leaders
24.8 ppg Randy Foye (MIN)
13.2 rpg James Singleton (LAC)
7.6 apg John Lucas (HOU)
2007 Leaders
42.0 ppg Marcus Banks (PHX)12.0 rpg Amir Johnson (DET)
6.4 apg DJ Strawberry (PHX)2008 Leaders
29.9 ppg Jerryd Bayless (POR)13.5 rpg Kevin Love (MIN)
7.3 apg Ramon Sessions (MIL)
2009 Leaders
26.8 ppg Anthony Randolph (GSW)
14.8 rpg Joey Dorsey (HOU)7.3 apg Marcus Williams (MEM), Brandon Jennings (MIL)
No idea what an updated list would look like, but that's a lot of guys who dominated summer league who never amounted to much, you know? Heck, even last year, the summer league's third leading scorer (Jordan McRae), second leading rebounder (Jerelle Benimon), and second leading passer (Tre Kelley) didn't contribute at all in the NBA.
Again, though, the flip side of that is a lot of disappointing guys in summer league have turned into good pros:
http://www.complex.com/sports/2015/07/nba-stars-terrible-summer-league-debuts/It just doesn't mean a lot.