Hybrids do involve extra parts, but the wear/tear is split across the drivetrains to an extent.
Think if you have a set of regular "all season" tires and a set of winter tires. You have twice as many tires but the wear is split across the sets.
Of course you aren't splitting it to that degree, but you aren't just wearing 2x the parts either. In particularly, the Toyota hybrid system at least has been proven to be highly reliable. Part of this is the highly reliable transmission (eCVT) they use and some other parts (like the traditional starter motor) that aren't needed.