Does Nokia make too many different Lumia models?

Nokia seems to be falling into HTC's former situation with having a confusing product portfolio with too many phones:

Lumia 1020, Lumia 1520, Lumia 1320
Lumia 920, Lumia 925, Lumia 928
Lumia 820, 822, etc.
Lumia 720
Lumia 620, 625
Lumia 510, 520, 521

These really need to be whittled down – all it does is just confuse consumers and diffuses marketing. Why do the 920, 925, and 928 coexist? Why are there so many midrange levels between flagship (1020/920/925/298) and low-end (520)? Why do the 520 and 620 have almost identical specs? Nokia really needs to whittle down the line - keeping track of it all is difficult even for the tech-savvy.