I have a Fender Ultra Stratocaster with SSS configuration. The pickups are branded as Ultra Noiseless™ Vintage Strat®. I use Ernie Ball Mighty Slinky Nickel Wound Electric Guitar Strings, 8.5-40.
Initially I thought it was my action that caused the weak sustain on >20 frets on high E string. I adjusted my truss rod and raised the saddle. That did help. But I ran another experiment. I wanted to eliminate frets from the variables. I picked a note on 22 fret (highest) on high E string and a note on 22 fret on low E string. The sustain was drastically different with low E ringing much longer.
It's reasonable that my pick can transfer more energy to a thicker string, hence low E rings longer than high E. But I think the sustain is unreasonably weak on high E string, compared to my PRS CE24.
Another speculation I have is that my pickups are too high? Or the magnetic poles too high? I noticed that Fender's Noiseless Pickup still uses staggered pickup poles despite the guitar has a compound 10-14 inches radius neck.
Would this affect sustain and I can't do anything about it? I can lower the overall pickup height but cannot adjust the staggered poles (unless I swap pickups but that's a lot more effort than making adjustments)