I see performance between 9mm and .38sp as a wash. As others have observed, the 9's wheelhouse lies in lighter weight bullets which compliment the small case and higher pressure. Once the weights get up over the 147gr you'll see .38sp gain an edge...and it can keep going.
IMO almost everything .38sp is marketed toward lightweight snubby revolvers where most people want a balance of performance and shootability, basically a low recoil alternative to .357mag...so loads like the 135gr Gold Dot are really about as much as the remfedchester bunch is willing to go.
9mm is first and foremost a pistol round, meant for recoil operated guns. It has to be loaded to sufficient pressure and performance to insure reliable function across a broad range of guns. So it makes sense that 9mm isn't going to look too mild from a snubby since it's essentially the same amount of 'runway' as a 3.5" pistol.
.38sp is loaded across a pretty broad range of pressures because it can without affecting reliable function of a revolver. You want wadcutters at 600fps, no problem. You want 158gr at 1000fps from a snubby, it can do that too. Being able to use lead bullets offers it the ability to drive heavier slugs pretty fast, faster than 9mm sometimes, with about half the pressure.