Pop electronic and pop rock are just very simple. The structure of these songs is easy to understand and easy to listen to. Verse-chorus-verse-chorus-bridge-chorus-chorus-fadeout. Easy peasy. The mark of a great pop song is the hook; that bit of melody that digs right into you.
Take a look at the history of American music. A little after the swing era, music sort of "split" in two directions; one was towards increased complexity (bebop, etc.), and one was towards simplicity (rhythm 'n blues, rock, etc.). The simple stuff became much more popular because it was easier to listen to, easier to dance to, and easier to play. Rock continued to evolve and spawn different off-shoots but the simplest and most accessible forms of the genre were always the most popular.
Electronic music is the same way and pop electronic music borrows a lot of the same ideas from pop rock; catchy hook, diatonic harmonies, simple chord progressions, verse-chorus-bridge song structure, etc.
Also just want to say that there's nothing bad about any of this.