there is more of a difference than just the pickups. Squier Strats, at least most of them, are made of solid wood, while fenders are made of poplar/alder/ash, etc. The wood Squiers use is crap, and your Squier will always be crap because of that.

However, you can learn many a lesson by taking it apart, putting new stuff on, changing pickups , etc, learn the customizations on a guitar.