Its not irrelevant. It's the entire point.
The whole idea was that Sprong wasn't getting opportunity here. As soon as he got it he started filling the net immediately, to the shock of nobody who's followed his career and saw his talent. The question was never "can the Pens' other RWs perform better in the top 9 than Sprong can with 8 minutes a night on the 4th line?", because that would be nonsense.
I'm not "just saying" it, I'm supporting my position. Rust was a tire fire in the top 9 this year (on both wings), Hornqvist was injured, and Simon was used primarily on LW to start the year...and Sprong wasn't given a chance in the top 9 regardless.
The idea that he was logjammed by better options doesn't hold water - not based on my opinion or yours, but by the facts.
He outpaced him this year considerably with far lesser linemates and opportunity. That's not nothing. Now we're seeing how he can produce when given decent minutes and opportunities with a scoring line center, an advantage that Rust has squandered all season until very recently.
Go ask if they regret it. I'll go watch.