1. Aftermarket suck.
2. OEM are $$$$$
If that’s an issue leave them alone. Used OEM > aftermarket.
3. The 2000 fuel pump didn’t fail - the pump cap and/or oring failed. You could have replaced that cap and installed a Viton oring. I have both and would shipped you both for $20 or so.
If a current Subaru has that same 2000 fuel pump cap - replace the cap and print with a viton oring. Or have one ready in the glove compartment if you’re handy and the cover plate screws aren’t all rusted. im not sure if 2005 Imprezas have that cap.
The pumps can fail and quarter million miles is a lot. The OEM pumps are really good so they probably are original. But...there are better places to pay attention.
A: at that mileage the alternator is more likely to fail and strand you and take out the battery than the pump. Replace that with OEM before the pump. If it’s an aftermarket alt then it’s even more likely to fail
B: same with the starter. Except you don’t need to replace, install new contacts and plunger. If it’s aftermarket buy a used OEM and install new contacts and plunger. $20 or less and it’s really easy.
those are far more likely to leave you stranded and cause additional issues than the pump unless you have the aforementioned pump cap oring issue.
Once all of that is taken care of then think about the fuel pump.
I think because starters, pumps, and alts use expensive metals like copper - that’s one reason aftermarket are so bad for these items. The aftermarkets probably lack quality control for type, quality and how much of those expensive windings and Copper is used. That’s just a guess, but no matter the cause I’ve seen top brands, new, rebuilt, reman, lifetime warranty all fail.