PER is a theoretical stat. You are a clown to quote that. To take what a player does in 10-15 minutes per night and assume that he can keep it up for 30-35 is not realistic. Wiggins actual stats are very similar to Porter's. For instance, they both average 19 ppg.
ANd they both play a similar number of minutes, Wiggins at 33.3 and Porter 31.3. Thus a comparison of PER is warranted.
Let's go with Per 100 possession stats since that is pace agnostic, all data from basketball reference
Points: Porter 30.0, Wiggins 26.2. Advantage Porter - and this was with Porter being the #3 option for 2/3 of the season. Wiggins was the #2 guy from the outset.
Field goals made: 11.5 Porter, 10.0 Wiggins. Advantage Porter
Field goal percentage: Porter 54.2, Wiggins 47.7%. Advantage Porter
Threes made: Porter 4.4, Wiggins 2.8. Advantage Porter
Three point percentage: Porter 44.5%, Wigging 38.0%. Advantage Porter
Two point percentage: Porter 62.8%, Wiggins 52.9%. Advantage Porter
Free throw attempts: Porter 3.5, Wiggins 4.7. Advantage Wiggins
Free throw percentage: Porter 79.1%, Wiggins 71.4%. Advantage Porter
Rebounds: Porter 11.5, Wiggins 6.9. Advantage Porter
Assists: Porter 1.8, Wiggins 3.3. Advantage Wiggins
Steals: Porter 1.8, Wiggins 3.3. Advantage Wiggins
Blocks: 1.4 each
Turnovers: 2.0 Porter, 2.5 Wiggins. Advantage Porter
Offensive rating: Porter 125, Wiggins 107. Advantage Porter
Defensive rating: Porter 112, Wiggins 111. Advantage Wiggins
PER (and keep in mind their minutes are very similar): Porter 20.6, Wiggins 15.0. Advantage Porter
True shooting percentage: Porter 63.3%, Wiggins 56.8%. Advantage Porter
Win shares per 48: Porter .173, Wiggins .080. Advantage Porter
Box +/-: Porter 3.0, Wiggins -0.7. Advantage Porter
Value Over Replacement Player: Porter 2.4, Wiggins 0.8: Advantage Porter
And Porter finished the regular season 20th in the league in field goal percentage, 9th in three point percentage, 12th in two point field goal percentage, 4th in effective field goal percentage, 7th in true shooting percentage, 17th in offensive rating