The biggest reason your cheap Strat sounds poor is due to the use of ceramic magnets and steel pole pieces in the pickups. Even in middle of the road Strats you can find such pickups sometimes. These pickups are not made to sound good. They're made to make noise and save money. No Strat pickup was made this way in the early days when they were first designed, they were designed to sound good, with alnico rod magnets.
Here's a set of Strat pickups with alnico magnets. These sit nicely between the ceramic rubbish, that you can find stock in many Strats, and boutique offerings (such as our exclusive Alegree pickups). These use high end components and design, but are made in bulk to a great price point.
Alnico 2 rod magnets give a smooth, silky and singing tone. These are more mid focused than their alnico 5 counterparts. They have less sting in the treble end and a softer bass response.
Magnets: Alnico 2 rods
Modern style cloth covered output leads
Vintage style flatwork construction
Wax potted to prevent microphonics
Reverse wound / polarity for humless positions 2 & 4
Supplied with mounting screws & springs